Mr Maynard was appointed Pensions Minister in November after the previous incumbent Laura Trott became Chief Secretary to the Treasury.

Mr Maynard has been an MP since 2010, representing the constituency of Blackpool North and Cleveleys and has previously been a government whip and minister at the Department for Transport and the Ministry of Justice.

The Sunday Times, which broke the story, also reported that the MP claimed rent expenses for an office that doubles up as his local Conservative Party association’s headquarters. Equipment claimed on public expenses by MPs is meant for constituency work rather than political purposes.

The Independent Parliamentary Standards Authority (Ipsa) said the matter would be referred to the organisation’s compliance officer. The watchdog, which was established after the 2009 MPs’ expenses scandal, said it would be up to the compliance officer to establish the facts of the case before deciding whether to investigate the claims.

It said MPs can use their offices for party political purposes as long as it is part of a pre-agreed sub-letting agreement.

Labour Party chairwoman Anneliese Dodds has written to Rishi Sunak to encourage him to ask the independent adviser on ministerial interests, Sir Laurie Magnus, to look into the claims. She said that, if the allegations are true “it is hard to see how such behaviour is consistent with the ministerial code.”

Ms Dodds said: “These are extremely serious allegations. It would be indefensible if a serving minister is found to be using taxpayers’ cash to fund party political materials.”

The Liberal Democrats have called for Mr Maynard to have the Tory whip suspended and be removed as a minister while a probe takes place.

According to The Sunday Times, Mr Maynard told an activist in his local Tory constituency party that it “made no sense” to create a separate office for political activity and such a move would not be a “good use” of party funds.

Since his election in 2010, Mr Maynard - who was made Pension Minister in November - has spent £106,000 on printing and related costs, according to analysis by the newspaper.

Laura Trott, the chief secretary to the Treasury, told Times Radio on Sunday: “Paul believes he had the right arrangements in place. He said he would abide by any rulings. This is ultimately a matter for Parliament.”