Tory councillors could be forced this week to vote on whether they support gay marriage.

Labour members say Medway Council should pledge explicitly to support the civil unions, which have caused rifts among Conservatives in Westminster and in other parties such as UKIP.

They have drafted a motion to be voted on by all councillors at a full council meeting this Thursday – but it could descend into a political row.

The motion calls on the council to acknowledge the last Labour government’s “positive efforts to support lesbian, gay, bisexual and transgender rights”, such as equalising the age of consent at 16, introducing civil partnerships and gay adoption rights.

The motion also calls on council leader Rodney Chambers (Con) explicitly to write to two of Medway’s Conservative MPs to persuade them to support gay marriage.

Although Chatham MP Tracey Crouch supports same-sex marriages, Gillingham and Rainham MP Rehman Chishti, who is also a councillor, has said he is against them. Rochester and Strood MP Mark Reckless has said he is undecided.

The motion asks for: “The chief executive and the leader of the council [to] write an open letter to Mark Reckless and Rehman Chishti requesting they vote in favour of any parliamentary vote supporting equal marriage rights.”

It was drafted by Cllr Tristan Osborne (Lab) and submitted by Cllr Teresa Murray (Lab - pictured left), both of whom claimed it was not a party political move.

Cllr Murray said: “It is important the council sends a clear, united and cross-party message that we back the coalition government’s policy for equal marriage, which is supported by Labour.”

A bill before parliament has proposed giving gay couples the right to civil marriage, over and above the right to civil partnerships, but would allow religious groups the choice of whether or not to perform ceremonies.