Thousands of people have rallied in Singapore against plans to build homes on two forested sites in a large public display of concern over how the land-scarce city state should balance housing demand with conservation.

The projects have brought renewed urgency to a long-running debate over land use: activists say remaining mature forests should be protected, while the government says conserving more greenery would mean fewer homes for Singaporeans.

Residents, nature lovers and conservation advocates gathered at Hong Lim Park on Sunday to protest against redevelopment plans affecting Maju Forest near Clementi’s Sunset Way and the greenery around Gillman Barracks.

Many of the rally’s participants were dressed in red and green, with some handing out fliers showing mock-ups of barren plots at the earmarked sites to showcase the outcome should the projects be implemented without sufficient protection of the green spaces.

They chanted: “Hands off, hands off Gillman! Hands off, hands off Maju!”

Singapore’s Housing Development Board (HDB) announced last month that it planned to build homes at Clementi’s Sunset Way and Gillman Barracks, which would see the clearance of some 15 of 23 hectares (56.8 acres) of Maju forest and at least 10 hectares of the forest near Gillman.