Local farmers have already been under three months of stress with high rainfall in the area preventing harvesting of oysters since early December last year.

Read more: Rains and sewage spill put Camden Haven oyster growers under pressure

Armstrong Oysters owner Brandon Armstrong said recent sewage spills are a disaster for growers because they come with a mandatory closure of the Camden Haven River.

"It's been really frustrating with the rain over December and January. On the back of that we have had three sewage spills in the estuary in the last three months, it's been very frustrating," Mr Armstrong said.

"The problem begins when stormwater gets into the sewer lines and mixes together before bubbling out as a toxic mix of sewage.

"At the moment we are lobbying council to get some of these areas fixed because each time we get a sewage spill we have to close down the river for 21 days. It's certainly not a good look for the community."

Mr Armstrong said growers have already lost more than nine weeks from their traditionally popular selling season.

"We are about to have meetings with the Port Macquarie-Hastings Council and get the NSW Environment Protection Authority involved," he said.

"These things need to be fixed and we have been dealing with council for 15 years about sewage spills.

"Council need to recognise that sewage spills affect farmers."

An NSW Environment Protection Authority spokesperson said the EPA is investigating sewage issues in the area.

"The EPA is investigating the circumstances surrounding the sewer overflow in Camden Haven River and is liaising with Port Macquarie-Hastings Council and oyster industry representatives on the issue," he said.

"Based on information from council and other relevant stakeholders, the EPA is looking into whether the overflow has been managed in an appropriate manner.

"The EPA was notified of the sewage overflow by council and an oyster industry representative. Council is required to advise the EPA of a pollution incident under the terms of their Environmental Protection Licence."

Port Macquarie-Hastings Council has been contacted for comment.