Brian Baldwin, employers chair on the National Joint Council which negotiates for manual and white-collar workers, said a clean break by Scotland would be a 'disaster for local government in the UK'.
The Convention of Scottish Local Authorities has unanimously backed a separate Scottish negotiating body. It wants one in time for next year's pay round.
COSLA members say a separate body is inevitable under a Scottish parliament with responsibility for local government funding.
'I'm hoping COSLA will have another look at leaving the NJC - they have been very, very good allies,' he said.
Unions have also told COSLA they don't want separate negotiations, and have insisted employers reveal their plans for a separate council.