Hawke's Bay District Health Board Medical Officer of Health Dr Nicholas Jones yesterday said a decision about whether to lift the swimming warning at Pandora Pond would not be made until next week.
"However, some of the results we have seen this week are reassuring," he said.
"We want to make sure we have looked into possible causes of contamination thoroughly.
Next week we will be in a better position to do that and provide the public with more confidence that the pond is meeting recreational water guidelines consistently."
Hawke's Bay Regional Council this week said recent samples had been clear, but could not provide an update on its testing yesterday.
Council group manager resource management Iain Maxwell has said staff were working to narrow potential sources down - Pandora Pond's location meant possibilities ranged from birdlife, boats dumping sewage to industry ruminant.
Staff were taking daily samples at five locations around Pandora Pond and Ahuriri Estuary. Smaller samples are returned between one and two days. If one comes back with high bacteria readings a larger sample is sent for faecal source tracking.
This can take several weeks to return, but identifies if a contaminant is ruminant, avian or human, so staff can begin tracing the source.
Having been closed for over a week, a number of events based at the pond have had to be relocated or cancelled.
Organisers of the Tremains Triathlon event, to be held next Sunday, have replaced the swim/kayak and stand-up paddle board led in Pandora Pond with a 2km walk/run as a result of the contamination.
"The health and safety of our competitors is the main priority for us and we believe it is in everyone's best interest to make this decision early to allow time for competitors to adjust to the new leg and/or make arrangements as necessary," a Tremains spokeswoman said.
"This change means that the event will be solely based from the new finish area at the Meeanee Quay Reserve."
The closure of the pond has also meant the move of a Canoe Polo Hawke's Bay tournament last weekend, and the suspension of some school activities.
• Entries for the March 11 triathlon are still open at tridentresults.com/event/190.
For up-to-date information, visit tremainstriathlon.co.nz. Questions can be sent to Tremains Triathlon at Tremainstri@tremains.co.nz