The Express was told that "three or four" Tories on Fylde Council are looking to jump ship.
The claim came from Bill Whitehead, who called the parish poll on the closure of St Annes swimming baths.
But Coun Coombes dismissed the allegations as "absolute rubbish".
Mr Whithead said there is now a concerted campaign to oust Coun Coombes, who some see as the architect behind the closure of the baths and other controversial developments in the borough.
Mr Whitehead predicted there could either be a "leadership challenge" within Tory ranks or that some councillors might "vote with their feet" and leave the party.
He claimed: "There are a number of Conservative councillors who are at this moment in time looking to move away from the Conservatives – even some of his own party are distancing themselves from him.
"There are councillors, I can't name them, that are talking among themselves and independent groups.
"At least two of the groups are talking to Conservative councillors. I'm aware of this from my personal knowledge."
Councillor Coombes said there was no foundation in the claim whatsoever and accused opponents of "trying to divide and rule" and of "undermining" what the authority was doing.
One Tory Coun Simon Renwick, cabinet member for culture and tourism, said he took the claims with "a pinch of salt".
He said he was not seeking to defect and added: "I would like to see the evidence. I think it is people playing a political game."