Community groups want to see physical action start immediately on fixing the algal bloom problem in Lake Tutira.
But scientific research on the issue will have to come first, ahead of any work on the well-known Hawke's Bay tourist destination.
The regional council and the Ministry for Primary Industries faced a community forum of about 70 people at Tutira yesterday, to give those farming, working or living in the area north of Napier a chance to have a say on the matter.
The regional council's environmental manager Steve Cave said the three-hour meeting was intense.
There was strong feeling from residents about what they wanted to see happen to the lake.
"They wanted physical work now in terms of putting a through-flow into the lake, investigation into a hydro scheme and what the outcomes might be."
He added: "The council's science response to the problem reinforced that we are not able to go in and do major physical work without the proper justification and proven science."
Mr Cave said he understood some people were not happy with the need for more time to use science to come up with the solutions.
"But there was strong support for all of the community groups to work closer and to see if there is a way we can have the Tutira catchment recorded as a priority, or at least a catchment management plan drafted for the wider area."
People were also critical of the ministry for its hydrilla eradication scheme, under which it had introduced grass carp in 2008 to eat out the problem weed.
"There was a feeling from the community that the carp were responsible for the algal bloom but the science shows that they are not.
"Algal bloom is a combination of factors occurring over a period of time, and has been seen at the lake in the past."
Mr Cave said it was important to continue with initiatives such as retiring farming land in the Tutira catchment, so it could be turned into areas where trees could be planted and used to remove nutrients from heading toward the lake.
The issue of the lake's outlet also came up at the forum and the need to clear it so water could flow and circulate.
The lake's stagnant condition was contributing to its problems.
"We have started a section of that but to proceed fully we need the endorsement of the landowners of that part of the lake."
The council's environment committee was also briefed on the problems facing Tutira at its meeting in Napier yesterday while Mr Cave was at the forum.