Protesters banged drums and chanted their opposition to proposed flats in Whitehawk.
The group staged a demo outside Hove Town Hall before Brighton and Hove City Council’s policy, resources and growth committee meeting.
The committee then heard from a deputation supported by 12 people opposed to the flats on a patch of green space with a path up to the Race Hill.
Eileen McNamara, representing the Save Whitehawk Nature Reserve Group, asked councillors to think again about the proposal to built 217 flats on Whitehawk Hill.
Five tower blocks are planned for the site on the edge of the Whitehawk nature reserve, off Swanborough Drive, as a social housing project.
The scheme has been drawn up by the joint venture between the council and Hyde Housing.
Ms McNamara said that Whitehawk was the most deprived area of Brighton and needed green spaces rather than concrete blocks.
She said: “I speak to people who use this path on a daily basis. They are incensed. It is as if we do not matter.
“People in the flats regard the nature reserve as their back garden. They do not want it built on.”
She said that since September more than 100 people had attended a public meeting against the project.
Another 100 people joined in the historic beating of the bounds last month.
She added: “We as a community will continue to campaign until this building scheme stops and another site is found.”
In the written deputation the local infrastructure was described as “at breaking point” as 103 new homes were recently built in the valley and more are planned for the Swanborough Drive playground.
Labour council leader Daniel Yates said that the council had to build 1,000 low-cost homes across the city.
Cllr Yates said: “The Whitehawk site is one of the first of three we are considering.
“The city is in urgent need of low-cost hosing, with high house prices and low incomes plus an ageing population and 12,500 on our housing register.
“Social housing makes up a small proportion of housing in the city, 9.8 per cent is owned by the council.
“There are a number of ways we are looking to increase this supply of low-cost homes in the city.”
He said that a detail ecological landscape study was under way.