Organisers say more than 2200 people walked through the Cleveland CBD on Sunday protesting a development slated for Toondah Harbour.
The 'Walk for Toondah' was held by the Australian Conservation Foundation.
The crowd aimed to raise awareness of potential threats to the environment if the Toondah Harbour development by Walker Corporation goes ahead.
Walker Corporation's plans for Toondah Harbour include 3600 dwellings, a longer and deeper shipping channel, a ferry terminal and marina, a swimming lagoon, conservation areas, waterfront retail and commercial space.
Conservation groups who organised the march await the release of the development's Environmental Impact Statement (EIS) and plan to oppose the project.
Walker Corp Toondah Harbour project lead Rabieh Krayem said the EIS had gone beyond regulatory guidelines by engaging a panel of 12 independent scientific experts to guide the process.
"We are required to show that all significant impacts on the natural environment are either avoided, minimised or offset. The project will not be approved otherwise," he said.
ACF's Bayside's Tania Kromoloff said many residents did not support the development
"Our community surveys show 85 per cent of locals are opposed to this proposal and fear its impact on the birds and wildlife in the Moreton Bay Marine Park and a local healthy koala colony," she said.
"We've had 2200 people show up and everyone is against it.
"We want to save Toondah Harbour, protect the koalas and the migratory shorebird habitat.
"There's plenty of reasons why residents in this area don't want this project to go ahead."
Attendees were concerned species like koalas, dugongs, sea turtles and eastern curlews could lose their habitat through the development and become extinct.
Indigenous elder Norm Enoch said Ramsar land was Quandamooka land and needed to be protected.
"The eastern curlew comes from Siberia and lands around Cleveland at Toondah Harbour," he said.
"To build up their strength, they eat for a couple of months so that they can fly back, but we need to look after our rare birds; otherwise, they'll end up on the extinction list."
Division nine Councillor Adelia Berridge said councillors were told they could be excluded from involvement in upcoming Council discussions of the development if they attended the walk due to a conflict of interest.
Bowman Greens Candidate Ian Mazlin said the Greens would push the next government to reject Walker's proposal.