Auckland and Waikato tangata whenua representatives say the agencies charged with looking after the Hauraki Gulf need to step up and start improving the waterway.
The Hauraki Gulf Forum on Tuesday released its third major report on the health of the water.
It says large amounts of litter continue to enter the gulf, some common wading birds are declining and 13 whales have been killed
after being entangled in mussel spat lines or injuries consistent with being hit by a boat.
The technical officer for the tangata whenua group, Mike Baker, says it is worrying that three years on, the state of the Hauraki Gulf is still poor and is showing a decline in many areas.
Mr Baker says agencies need to start sharing information and tangata whenua need to be involved in some of the management initiatives which could improve water quality.