Campaigners are seeking more detail about proposed leisure facilities at the coast amid growing protests.
They say the plans at the historic Spanish Battery, overlooking the harbour at Tynemouth, would spoil one of the town’s last peaceful places.
More than 2,400 people have now signed a petition, launched by the Friends of the Spanish Battery, urging North Tyneside Council to reject the scheme.
The Northern Property Group has submitted an application to build a cycle hub, which includes leisure facilities and a shop.
The scheme is planned on a 1,200 sq m site in front of the grade II-listed Tynemouth Volunteer Life Brigade Watch House Museum close to the Old Coastguard Cottages.
The site, called the Watch House Garden, is owned by the developers, but locals say the plans show that adjacent council-owned land will also be needed.
The Friends of the Spanish Battery say a number of key issues have still to be addressed and have asked a series of questions via an open letter to the developers.
In their response, the developers say many of the questions were answered during consultations and their vision and intentions are set out on the North Tyneside Council planning portal.
Concerns include the number of covers at the café and whether alcohol will be served. Other questions relate to numbers of lorry movements during construction and how much public open space is required.
Lee Mitchell, vice-chairman of the Friends of the Spanish Battery, said: “People need detailed answers to judge the impact on the surrounding area.
“They are seeking A3 use which will mean a restaurant or café but we have few details beyond that. To judge the scale we need to know the number of covers so we have an idea of customer numbers.
“From what we’ve learned so far, the development would certainly be detrimental to the character and appearance of the conservation area and the setting of the nearby listed building.”
Previously, Josh Boyle, one of the founders of the Watch House Garden project, said the plan would increase the green space on the Battery.
He said: “Our designs turn the current private garden and unusable, overgrown slope into an accessible green space for all the public to enjoy, essentially increasing the green space available on the Spanish Battery.”
Opponents are urging people to register objections with North Tyneside Council before the August 17 deadline.