The Democratic Unionist Party’s Chief Whip has defended his party’s opposition to equal marriage in Northern Ireland.

On Monday, the DUP once again tabled a petition of concern, using Assembly rules to effectively ban a vote on the measure.

The Assembly is due to debate equal marriage tomorrow.

In a statement released before the veto had been announced, DUP Chief Whip Peter Weir said: “It will be exactly one year since this motion was last debated in the Assembly.

“On that occasion a cross party majority voted against the introduction of gay marriage in Northern Ireland. Indeed, the majority of MLAs against the motion increased from the previous debate.

“Same-sex marriage is not an issue of equality or human rights and the Northern Ireland Assembly is entirely entitled to take a view on the issue, even if that happens to be different to other jurisdictions. Differing laws in differing jurisdictions is the very essence of devolution.”

Mr Weir added: “The DUP is the only major party with a consistent view on this matter. This Sein Fein motion will only result in further embarrassment for those parties and individuals who avoid telling the electorate where they stand. Although, for those who will listen to their conscience above their leadership, we commend their courage.”

Sinn Fein, the Social Democratic and Labour Party (SDLP), the Alliance Party, NI21 and the Greens, all support equal marriage.

The UK Independence Party’s sole member of the Northern Ireland Assembly yesterday confirmed he would have voted against the motion in the event of it being debated.

The DUP has continually resisted supporting LGBT equality across the board. First Minister Peter Robinson and Health Minister Edwin Poots have refused to lift Northern Ireland’s lifetime ban on gay and bisexual men giving blood.

Demonstrations by equal marriage campaigners took place in Northern Ireland last month on the eve of the first same-sex marriages in England and Wales in order to highlight the equality gap in the province.

Same-sex marriages conducted in England and Wales are currently only recognised as civil partnerships.

Amnesty International has said equal marriage in Northern Ireland could eventually be secured in the courts – in order to bypass the DUP’s opposition.