Key findings recommended that Maritime New Zealand should:
• Consult the Government about the demands of a major maritime casualty and Tier 3 oil spill response involving multiple or related risks.
• Review the national strategy, in association with the Government, to ensure it "properly covers the variety of serious maritime incidents to which MNZ, alone or in partnership with other agencies, may need to respond and any legislative or resourcing implications arising".
• Advocate for a wider policy response framework addressing non-oil pollution and natural resource protection, and review arrangements for wildlife protection
• Improve communications and arrangements with volunteers, the community and iwi.
In his review, Mr Murdoch said the pressures of the disaster had caused Maritime New Zealand across its systems and response machinery, to "buckle initially".
"Some of its planned and exercised response functions had limited resilience to begin with and were impaired in ways that might have damaged the response as a whole," he said.
"Others had to be reinforced and scaled up, and that did not always happen quickly or seamlessly."
He said the agency's initial response, both at the frontline and rear, "struggled to achieve functionality".
"Some of its shortcomings were inherent in the gap between MNZ's planned capability and the scale of the incident," he said.
"Others arose from deficiencies in the planned capabilities, response doctrine and structures, which might not have shown up in a lesser event but were exposed by the complexity of the Rena incident and the multiplicity of the challenges it posed."
He said the problems of administering and servicing frontline operations on the unprecedented scale required in the response had been underestimated and under-planned.
While they were progressively overcome during the response, this did not happen quickly or easily, he said.
The response was limited in part, but not fundamentally compromised, by deficits in MNZ's technical capabilities, namely equipment.
While the agency's technically specialised staff delivered soundly - for example, in ship inspection and investigation) - Maritime New Zealand may have "lacked depth" in environmental analysis, he said.
But Mr Murdoch gave the agency better marks for its long-term response, highlighting that preparations for oil on shoreline and beaches were "satisfactorily executed" despite being technically impaired.
On-board oil removal operations became "very effective" and reduced risk, dangerous goods risks were managed down gradually, and containers and container debris removal operations on water reduced risks to beaches, sea-lanes and shorelines.
Maritime New Zealand director Keith Manch said work was already underway to build on the lessons identified in the review.
The agency had worked closely with departments to improve communication in the event of a major event.
It had undertaken a comprehensive review of the National Response Team, a group of trained oil spill responders from around the country who form the core response team for a Tier 3 oil spill incident, resulting in greater resources to support oil spill response and the national oiled wildlife response.
Among other improvements, it had reviewed international support arrangements for oil spill response, developed additional specialist support arrangements in areas such as well control and hazardous and noxious substances, undertaken new training for staff, and was reviewing the national Oil Spill Response Strategy.
The agency was also reviewing its purchasing system to improve financial management during the peak of a response.
Transport Minister Gerry Brownlee said the review made it clear that the Rena grounding was one of the most complex maritime response challenges in the world, and would have tested the limits of any plan.
Improvements that would be carried under a new 2.05 million package of work included:
• Developing a wider maritime incident response strategy extending beyond oil pollution response to including salvage and volunteer plans
• Clarifying functions and strengthening capability around salvage
• Reviewing the response management structure, including increasing skills through secondment and training
• Increasing cross-government coordination, including a national emergency management exercise to test whole-of-government readiness for maritime incidents
• Improving procurement and supply processes to ensure financially prudent expenditure during an incident response.
Greenpeace recently released its own projection on how an oil spill would affect the coastline, but Anadarko's own projection, included as part of its discharge management plan application to Maritime New Zealand, is being withheld.
It is expected to be made public later this month.
Maritime New Zealand's general manager of safety and response services, Nigel Clifford, has told the Herald there was "no question" a well blow-out would be damaging, but he said risk remains extremely low.
"In the overwhelming majority of cases, a well blow-out does not render the drilling rig non-operational, so the same rig is immediately in position to drill a relief well."
In the event of a major incident, resources would be available from a variety of sources to assist in the response, and in the first instance, the operator's own support vessels would be utilised.
"There will also be a number of appropriately equipped utility vessels operating around other drilling rigs off New Zealand and these would be seconded to the response effort as required.
"As was the case with Rena incident, any requirements for vessels beyond what is nationally available will be sourced from overseas."
Notwithstanding this possibility, the Well Control Contingency Plan for each exploratory operation would detail if a relief rig is required and, if so, how it will be made available, he said.
"No country, with the possible exception of the United States, maintains a domestic capability to respond to all possible oil spill events and this is the basis of international agreements on responding to such spills."
A new report on the effects of oil pollution from the Rena's grounding has shown few long-lasting impacts on Bay of Plenty maritime habitats - but the environment had not yet returned to its pre-Rena state.
The 460 page report covers the first two years of ongoing survey and research work, and details one of the most comprehensive, multi-disciplinary studies ever undertaken in response to a marine pollution incident.
University of Waikato's chair in coastal science, Professor Chris Battershill, said initial concerns that oil would have a long-lasting and negative impact on beaches and fisheries could mostly be put to rest.
"While there is still some evidence from time to time of heightened Rena-sourced contaminant levels in kaimoana species on some of the beaches, and northern parts of Motiti, the vast majority of kaimoana and other species have survived, and no evidence has been found of any catastrophic die-off," he said.
He said the report covered the immediate and medium-term environmental response to the incident, and did not aim to give a comprehensive assessment of the long-term environmental effects, or provide a complete assessment of the "myriad complex interactions" surrounding the Rena grounding.
These assessments would be planned over the coming months, on top of ongoing postgraduate research work initiated by the first phase of monitoring.
"It will be prudent to continue to monitor key locations affected by tar balls and other debris over the next year to pick up any longer-term trends," he said.
"We also want to assess what impact the re-exposure to pollutants is having on kaimoana and other species."
In other findings based on laboratory studies done within the project, the impact of heavy fuel oil and the dispersant Corexit on juvenile finfish such as kingfish and flounder, showed effects at higher exposures.
However as the dispersant was used only briefly on the oil spill at sea, and given the strong offshore wind conditions at the time, there were no environmental effects, he said.
There was now little evidence of remaining oil or tar balls around the Bay of Plenty's coast, and oil washed up on rocky reefs has largely disappeared.
"Very little oil residue has been found in coastal beach sediment cores, which sample deeper down into the beach sands. However, some oil and other debris from the shipwreck and containers continue to wash ashore during storms."
The results back up what scientists suspected when early test findings were released on the first anniversary of the grounding.
At that time, 30,000 samples had shown that levels of PAHs (Polycyclic Aromatic Hydrocarbons) had dissipated in most areas of the Bay of Plenty.
