Campaigners opposing plans to shut one of Carmarthen's main roads to build a £50m retail centre have been told there will not be a referendum on the issue.
More than 200 people attended last month's public meeting
A public meeting called to try to force Carmarthenshire Council into holding a vote was attended by over 200 people.
But the authority has said protesters had misinterpreted the law and there was no provision for such a vote.
Developers plan to close St Catherine Street in the day but opponents said it would force traffic onto back roads.
The organisers of last month's meeting said they were calling for a referendum under the Local Government Act 1972.
They said they would go to court if the council failed to hold a public vote.
But the authority's head of administration and law Lyn Thomas said that the council could be acting unlawfully if it held the vote.
Developers said St Catherine Street must be closed to traffic
"We received the request for a referendum and have looked carefully at this request," he said.
"However, the Local Government Act 1972, which is the law being quoted for this request, does not give community meetings a right to demand a referendum on any matter.
"The county council would be acting outside of its powers should it concede to this request."
But the council said the public would have a chance to comment on the proposals during the planning process.
The scheme will see a new indoor market hall, Debenhams department store, cinema, bowling alley and other shops built on the former cattle mart site in the town.
One of those who attended the meeting, Sian Thomas, who lives on St Catherine Street, said the council had a "moral obligation", if not a legal one, to hold a referendum.
"More than 200 people were at the meeting. For people to be this motivated about it shows the strength of feeling," she said.