Plans include a relief road taking some traffic away from the town centre
Campaigners say they hope a protest walk in the seaside town of Abergele will help persuade council officials to rethink a new development plan.
Conwy council is setting out development proposals for the entire authority until 2022.
But some residents in Abergele say they are against plans to designate land in the town for a Gypsy and traveller site, and for more than 300 new homes.
They marched through the town on Sunday to highlight their concerns.
Under the proposals currently being considered by Conwy council, the Local Development Plan (LDP), would designate land near the town's A55 expressway roundabout as suitable for 220 houses.
A further 90 homes would be sited at the other end of a proposed route for a new relief road in the town. The road itself would also pass through an area set aside for a new Gypsy and travellers camp.
But Alasdair Rettie, chairman of the newly-formed Abergele LDP Action Group, said there was mounting opposition to the proposals, and said there had not been enough consultation on the plans.
"We believe that no-one wants a Gypsy and travellers site in the town," he insisted.
"We also believe that nobody wants to spend £10m plus on a relief road that will go through public open spaces, and effectively open up the whole south east side of Abergele to being built on."
In addition to Sunday's protest walk, the campaign group has also posted 4,000 leaflets to homes in the town, setting out their objections.
Mr Rettie said the group had also hired a planning consultant to help fight the proposals, and had held meetings with the Clwyd West MP David Jones and assembly member Darren Millar.
However, the campaigner said his group would only continue pursuing the issues "if the majority of the people of Abergele are behind us".
"And we believe that they are," added Mr Rettie.
A spokesperson for Conwy council said that the public consultation on the LDP was continuing, and had added extra dates to exhibition days on the plan to ensure "everyone has the chance to see the whole information, meet the planning officers, and give their clear opinion on the draft plan".