Daina Shipping Company, as the registered owner of Rena, has overall responsibility for the operation of the ship.
The Rena was carrying a variety of materials defined under the Resource Management (Marine Pollution) Regulations 1998 as harmful substances or contaminants.
They included heavy fuel oil and other oils, and 32 containers of dangerous goods including 40 tonnes of hydrogen peroxide, 23 tonnes of alkylsulphonic acid, 500 tonnes of ferro-silicon, 5.4 tonnes of trichloroisocyanuric acid, and 24 tonnes of potassium nitrate.
Other substances carried on board defined as harmful include bulk wine and operational waste. Items aboard classified as contaminants included animal pelts, dairy products, fabrics, cement and machinery parts.
A total of 121 containers of perishable foodstuffs were also on the Rena.
Captain Mauro Balomaga and navigation officer Leonil Relon were arrested shortly after the Rena accident. In February they pleaded guilty to 11 charges laid over the grounding.
The pair were sentenced in May to seven months' jail but served half the time and returned to the Philippines last month.
Maritime New Zealand director Keith Manch welcomed the guilty plea today.
"The completion of this prosecution marks another step in the response to the grounding of the Rena. There remains a lot of work to be done in the recovery process and MNZ continues to oversee the wreck removal process," he said in a statement.
Resolve Fire and Salvage continued to work on the removal of the Rena, while Braemar Howells/Unimar continued to collect debris from the seabed and beaches in the area, Mr Manch said.
Earlier this month an independent review of the response by Maritime New Zealand (MNZ) was announced.
It is expected the independent review will be completed in the first quarter of 2013. A separate investigation will be held by the Transport Accident Investigation Commission.
Daina Shipping representative Konstantinos Zacharatos, speaking from Athens, again apologised on behalf of the company to the Bay of Plenty community and people of New Zealand.
"This occurred as a result of human errors. I apologise for the actions of the crew, the accident and any damage caused.
"This is an accident no one wanted to happen but it did and consequently we take our responsibilities very seriously. Right from the start, Daina Shipping Company has used all resources available to it to address and limit any damage caused," he said in a statement.
"Together with the thousands of volunteers who assisted during the early days of this unfortunate event, we have managed to keep impacts contained to the absolute minimum, when you take into account what was at stake back then."
- NZ Herald and APNZ