Northern Ireland's Deputy First Minister Martin McGuinness has robustly defended his fellow Sinn Fein MPs after allegations they were fleecing the taxpayer over expenses.

And the Mid Ulster MP claimed the Government owed Sinn Fein millions of pounds in unpaid salaries.

Mr McGuinness said that he, along with Gerry Adams, Pat Doherty, Michelle Gildernew and Conor Murphy, did nothing wrong by claiming more than £400,000 on a pair of London flats.

In the past financial year, the five were reported to have claimed £105,000 on the flats, even though they do not take their seats at Westminster.

They do not take their seats because to do so would entail swearing an oath of allegiance to the Queen - and if they won't they don't get paid.

Mr McGuinness said he had been elected as an MP for the past 10 years, Gerry Adams for longer, and the other three for several years.

"The British Government does not give us one halfpenny of our salaries. In fact, if the truth be told, the British Government owes Sinn Fein millions of pounds.

The party, he said, made no apology to anyone for not taking their seats in Westminster - that was why they were elected in Republican constituencies - and people supported their stance.

They were simply taking in expenses they were entitled to.

He added: "The money does not go into our pockets. It employs people. It rents buildings. It buys computers. It does all sorts of things in the interests of the citizens."

Mr McGuinness made clear he was not lining his own pockets and, like the others, his money went to the party.

As an MLA at Stormont he was paid £42,461.52 in the financial year to April 2008. It was topped up with a further £64,136.95 for being Deputy First Minister - giving a total of £106,598.45.

But he said he got around £300 a week - the same as his driver.

He said: "I am the Deputy First Minister and an elected MP. I get roughly £300 a week from Sinn Fein, the exact same as the person who drives me to my work every week.

"I have no problem with that, knowing the rest of the money is being put into developing Sinn Fein and developing constituency offices all over the island of Ireland for the people of Ireland."

Mr McGuinness would not be drawn on Fermanagh and South Tyrone MP Michelle Gildernew, who claimed £21,000 for housing allowance in London but only £300 in travel expenses - suggesting few visits to the capital.

He said: "I can't deal with individual claims of other MPs except to say the vast bulk of MPs at Westminster are given a housing allowance."

Shadow Northern Ireland Secretary Owen Paterson, said: "It is unacceptable for Sinn Fein representatives, who won't even sit in Parliament, to claim hundreds of thousands of pounds at the taxpayers expense."

Ulster Unionist MEP Jim Nicholson said the claiming of huge expenses by absentee MPs was a disgrace.

He said: "I will continue to encourage Conservative colleagues to reform the system after the next election."