Watercare says it is hoping to make amends to improve the health of Auckland's Waitematā Harbour because it has "suffered a lot in the past 100 years".

After seven weeks, Ngāti Whātua Ōrākei on Thursday morning lifted the rāhui over the harbour at Ōkahu Bay, meaning swimmers can get back in the water.

Raw sewage spilled into it at the end of September when a storm and wastewater pipe burst, creating a sinkhole in a Parnell carpark and blocking the Ōrākei main sewer.

On Friday, Watercare met with Ngāti Whātua Ōrākei to discuss the next steps in the harbour's restoration. The two groups were joined by environment regeneration experts to find a way to get the water back to health.

Following the meeting, environmental care manager Nathaniel Wilson said the water quality was back to normal, but there were "subtle changes" that could take months or years to resolve.

"You just get a slight change in what makes up the ecosystem, so different things move in, other things move out. Just getting that equilibrium back will take some time."

While results showed it had affected the water quality of the harbour, he said, "there's not a lot to directly clean up".

"Natural processes will resolve that better than we can intervene."

The Parnell sinkhole. Photo: Desley Simpson

In the meantime, Wilson said action was being taken to restore the Waitemata Harbour from the poor treatment it had experienced in recent history.

"Through unfortunate circumstances we are in a position to do some good. It is very much acknowledging that the harbour has suffered a lot over the last 100 years, and this is an opportunity to start making things right."

He said Watercare was working alongside Ngāti Whātua Ōrākei and Revive Our Gulf to replenish "ancestral mussel - or kūtai - beds'.

Wilson hoped there would be opportunities with other habitat restoration projects around the harbour.

"That's artificial reef building, and planting habitat like seagrasses and seaweed."

This story was originally published by RNZ