Several green groups have staged protests in Ma On Shan, the site of a mobile exhibition to consult the public about boosting land supply.
The environmental group, Green Sense, accused the Task Force on Land Supply of exaggerating the territory's land shortage problem and favouring such options as reclamation and developing the periphery of country parks.
The Labour Party, meanwhile, said there are still a lot of farmland and brownfield sites in Hong Kong that could be used.
On Friday, a parallel task force set up by land activists accused the advisory group of trying to "brainwash" people into believing there is no space available for housing – with the aim of pushing the development of country parks and reclamation as the only alternatives.
The government's task force rolled out its five-month public consultation at the end of April, seeking public views on 18 options it has drawn up for finding land for housing.
The second phase of the consultation was launched on Saturday, involving large-scale public surveys.
The advisory group will compile a report for the government at the conclusion of the consultation process.