City of London Police said Sunday they are mulling whether to launch a probe into Adam Werrity, whose close links with former Defence Secretary Liam Fox sparked his resignation before the weekend.
Lawmaker John Mann, of the opposition Labour party, has asked the police to investigate allegations that Werrity used business cards which claimed he was an adviser to Fox -- despite having no official role.
"City of London Police can confirm is has received an allegation of fraud," said a police spokesman on Sunday.
"Officers from the force's economic crime directorate will consider the matter and establish whether or not it is appropriate to launch an investigation."
Mann is also considering a complaint with the Electoral Commission, which regulates the funding of political parties in Britain.
Fox, who played a key role in Britain's military campaigns in Libya and Afghanistan, resigned Friday after it emerged that his best man Werritty posed as a government adviser and took foreign trips with the minister.
Conservative party lawmaker Fox has also apologised to parliament and admitted Werritty had accompanied him on 18 foreign trips, and visited him 22 times at the Ministry of Defence (MoD) in London.
Fox stepped down Friday as reports emerged that financial backers linked to Israel and a private security firm had funded Werritty's first-class travel and hotel stays during his time with the minister.
Prime Minister David Cameron has ordered an inquiry into whether Fox broke the ministerial code of conduct. The results are expected within days.
Labour's defence spokesman, lawmaker Jim Murphy, called Saturday for a full investigation.
"Only Liam Fox knows the truth -- the whole country's entitled to know the truth and that's what we need to get to the bottom of," Murphy told the BBC.
Fox is the first Conservative minister to resign from the government and the second cabinet minister, following Liberal Democrat chief secretary to the Treasury David Laws last year.
Philip Hammond, the Conservative former transport minister, has been named as his replacement.