Unions and employers are pushing for a national agreement on single status by April. It will mean common working conditions for 1.5 million council workers, and its implementation is likely to be phased over a number of years.
MPO general secretary Graham Corless wrote in December's issue of the union's newspaper: 'I cannot see single status being anything other than detrimental to large groups of staff.'
He told LGC last week: 'The difficulty is that with tight financial constraints local authorities are unlikely to offer single status on the right sort of terms for staff to want to take it up. I'm not at all convinced that anybody can at the present afford single status.'
Manual staff will benefit most under the new agreement. They will have a shorter working week, and will share a pay scale with white-collar workers that could mean a higher ceiling on salaries.
Employers are insisting on more flexibility for councils to negotiate conditions locally to balance the cost of the changes.
Local authorities may decide to cut white-collar conditions to pay for blue-collar improvements, said Mr Corless.
'I would say the employers are now having serious doubts about its viability, although they may want to do an agreement in principle,' he said. 'I'm not sure they could even start implementing it straight away.'
Unison head of local government Keith Sonnet, who represents one of the three unions involved in the negotiations, said there would be substantial improvements in pay for low-paid workers, particularly women.
T&G national secretary Jack Dromey said: 'I do not share Graham's bleak view of humanity that the better off will object to long-awaited justice for the worst off.'