The chief executive of Carrick council has warned all council staff who are members of Unison that if they vote for a two-day strike they will lose two days' pay "and, for those in the pension scheme, the loss of two days' pensionable service."

Mr John Winskill, in a brief to staff about a national pay dispute, said: "A strike will not lead to any change in the employers' position."

Both the GMB and T&G unions had recognised that the new offer was the best that could be achieved.

Nationally, local government workers have been offered 2.475 per cent wage increase.

The offer includes an additional increase for the lowest paid that will take the minimum rate in local government to £6 an hour.

GMB and T&G members this week decided to accept the offer but Unison are pressing ahead with a ballot for strike action. Ballot papers are due to go out on Friday and close on October 26.

"Think carefully before you cast your vote," staff have been told at Carrick.

"The improved offer recognises the contribution the whole workforce has made to local government achieving the best efficiency gains in the whole of the public sector. And, in response to union concerns, it also raises the lowest rate in local government to £6 an hour. But the new offer stretches councils to the limit of their affordability and cannot be increased any further. There is simply no more money available."

The new local government offer is not staged but will be paid in full from April 1.

"If Unison members vote no in the strike ballot, then you will get the 2.475% increase (including the back pay due from April 1 in your pay packet before the end of the year," said Mr Winskill.