Conservative ministers would be "duplicitous" if they refused to give Scotland power over corporation tax at the same time as Northern Ireland, the SNP have claimed.

The Tory-Lib Dem government yesterday published plans to devolve control by Spring 2017.

The move came amid growing expectations that the Tories could try to rely on the Democratic Unionists come May.

David Cameron's party is understood to be looking at the possibility of a deal with the DUP if the general election results in a hung parliament.

Ministers said the tax move could energise an economy which for too long has been over-dependent on public sector jobs.

The legislation introduced is expected to pass before Westminster closes for the election and would allow Northern Irish politicians to set their own rate from April 2017.

The DUP have campaigned for the power, arguing that the Northern Ireland economy struggles to compete because of its land border with the Republic of Ireland, where the rate is a rock bottom 12.5%.

But SNP deputy leader Stewart Hosie said: "It would be completely duplicitous and utterly reprehensible if Westminster was to deny to Scotland what it is keen to offer to Northern Ireland."

That claim was rejected by Danny Alexander, the Highland MP and chief secretary to the Treasury.

He added: "Within the UK, the case for devolving corporation tax-setting powers to Northern Ireland is unique. It shares a border with Ireland, where a far lower rate exists, and the economy faces other special challenges."

The plan is a key part of the Stormont House Agreement signed before Christmas and designed to break the political stalemate in Northern Ireland.

Around 34,000 businesses are set to benefit.

First Minister Nicola Sturgeon has insisted that if Northern Ireland got the powers "then there is no argument that says (they) shouldn't also be devolved to Scotland".

Mr Hosie also called for the power to be given to Scotland on the same timetable as Northern Ireland.

"The fact that (ministers are) hopeful the UK Government can transfer the powers before the election shows how quickly it can be done when there is the political will.

"It also raises the question as to why, if Westminster can devolve corporation tax to Northern Ireland by May, they can't devolve air passenger duty and corporation tax to Scotland within the same timescale?"