Labour's coalition with the Liberal Democrats in the Welsh Assembly could falter over revelations it is set to halt to any further plans for widening proportional voting in Wales.

Labour may need to enter a second coalition with the Liberal Democrats to retain its hold on power in Cardiff Bay following next spring's assembly elections.

The Lib Dems helped Labour gain overall control

Details of Labour's draft manifesto have been leaked to BBC Wales and the document reveals the party does not want any changes to the voting system for local councils.

Labour's Priorities for Wales document states the party supports the existing first past the post system and fails to mention proportional representation.

But the Liberal Democrats' assembly group leader Mike German called for PR in local government elections at the party's autumn conference in Llandrindod Wells in Powys just last month.

One senior Labour source, however, told BBC Wales that the party would never accept such a move.

Negotiations

Currently, the 60 seats in the assembly are decided by two forms of voting system - the traditional first- past-the-post system and a list system, representing 20 seats in the chamber.

The Liberal Democrats have said that proportional representation for Wales' 22 local authorities is not a precondition for any new deal with Labour next year.

But the principle is a fundamental aspect of the party's philosophy and it is thought the Liberal Democrats will press the issue in its negotiations with Labour.

The Lib Dems want a better local voting system

Yet Labour's rank and file members are set against any such moves.

The Liberal Democratss are confused by the draft manifesto failing to mention PR, because the existing coalition sets out to promote the recommendations of a commission, which has urged a new proportional voting system in Wales.

Labour's coalition partners want concessions on the issue to pave the way for the party's future support.

But Rhodri Morgan is set to face calls from traditional party members to stick to the black and white print in the manifesto.

The Liberal Democrats' leadership has said it also wants increased investment in public services, and the strengthening of Welsh communities to be central to talks over a new coalition administration.