Thousands of litres of raw sewage is allegedly being pumped out of septic tanks at a well-known Auckland complex, towards a stream that flows into the sea.
That's according to locals living near Formosa Golf Resort, in the suburb of Beachlands.
A member of the public, who wants to remain anonymous, has supplied footage to 1 NEWS catching someone at Formosa pumping wastewater from tanks on site, down a gully.
A hidden camera has caught the alleged activity on film more than once.
A local resident told 1 NEWS he believes thousands of litres have been discharged every weekend.
"I come down here and walk my dog, I know that smell, that overflow smell, it was getting pungent, quite pungent" he said.
"I tracked it, traced it up, sort of did a bit of investigation work and followed it up, right up to where it's being pumped out from."
He claims the company's had issues with its wastewater treatment for years.
Auckland Council has tested the water in the stream but won't tell 1 NEWS the results, saying it's still investigating.
Regulatory Compliance Manager Steve Pearce said "an abatement notice was issued to the owner and operator of Formosa Golf Resort in Pine Harbour on 31 January due to our concerns regarding contaminants of wastewater discharge.
"The council is monitoring the site, has an open investigation into this issue and is following up with the organisation to ensure steps are being taken to mitigate the issue" he said.
Formosa Golf Resort refused our offers of an interview but in a statement its lawyer assured 1 NEWS disposal trucks are being used, to deal with the effluent.
He said "The company is investigating the allegations.
"The company has also taken immediate steps to upgrade its security and treatment plant".
He says "rectifying the waste water issues has been completely outside of the company's control", as until recently it's been unable to access the funding needed, due to legal proceedings."
Work to fix the wastewater treatment issue is now set to begin in the next two weeks.