Sainsbury's has said supermarket staff have been subjected to torrents of abuse from local residents over a planning application.
Checkout staff at the Crosby store in Merseyside have been yelled at by some shoppers for the past few weeks, the company said.
A £50m proposal to build a bigger store and regenerate the surrounding area was rejected by Sefton Council last month.
Sainsbury's described the shoppers' behaviour as "disgraceful bullying".
Former Conservative parliamentary candidate Debi Jones, who lives in the town, said: "Members of staff at the store have told me that they have been subject to verbal abuse by customers and people shouting at them as they came to work.
"This is disgusting, staff there are local people as well. I have seen some women who started as teenagers in the that store and have since become managers.
"The planning application has nothing to do with them, they are simply earning their living as any others do in Crosby."
The town has been divided since Sainsbury's submitted a planning application to build a superstore to replace its medium-sized supermarket.
A Better Crosby organisation had been campaigning for the supermarket giant to build a "reasonably sized" store, amid fears the superstore plan could change the character of the town and have a negative impact on local businesses.
"We are totally in favour of Sainsbury's and we would certainly not want to be associated with anyone abusing members of staff," said a spokesperson.
The group is hoping to work with the company to help develop alternative plans and are committed to "positive moves" for Crosby, they added.
Other people, however, want the development to go ahead because of the prospect of regeneration and increased footfall.
The council's planning committee rejected the supermarket's application, going against the advice it had from planning officers.
A Sainsbury's spokesman said: "It is not our in-store colleagues who decide the details of the planning application, so there is no justification for this kind of intimidating behaviour.
"We are currently reviewing our options in light of the planning committee's decision, and we will decide on our next steps in the coming weeks."