Conservative leadership candidate Andrea Leadsom has published details of her CV, after claims her previous roles in financial services were exaggerated.
Mrs Leadsom has made her experience in the City a key part of her campaign to be the next leader and prime minister.
Allies of the energy minister have said she is a victim of a concerted effort to rubbish a "stellar" career.
Mrs Leadsom, who was a leading Brexit campaigner, came second in the first round of voting in the leadership race.
Mrs Leadsom, a former economic secretary to the Treasury, will battle it out with fellow Brexit backer Justice Secretary Michael Gove on Thursday to join Home Secretary Theresa May on the ballot to succeed David Cameron.
Liam Fox and Stephen Crabb withdrew from the leadership race after the first round, and gave Mrs May their backing.
By John Pienaar, deputy political editor
Energy minister Andrea Leadsom's claim to have been a financial high-flier is under intense scrutiny.
Team Leadsom has made much of her background in banking. One friendly MP described her as having managed "hundreds of people and billions of pounds".
But the Times newspaper described her credentials as a senior banker as having been "politely but firmly undermined".
Robert Stephens, formerly of the investment firm Invesco Perpetual, had said "she didn't manage any teams, large or small and certainly did not manage any funds".
Ms Leadsom's CV also lists the post of Project Director at Barclays. "Director" was a managerial title, not a boardroom one.
A campaign helper told me she'd been unfairly attacked, but also admitted her experience may have been "bigged up" - exaggerated, in other words - by the MP who'd boasted of her high-powered background.
Mrs Leadsom's campaign has responded to a report in the Times - which claimed her career had been exaggerated - by publishing a summary of her CV setting out her various banking roles, including senior roles at Barclays and Invesco Perpetual.
Defence Minister Penny Mordaunt - one of Mrs Leadsom's backers - claimed there was a "concerted effort" being made to cast doubt on the leadership hopeful's background before entering parliament, and said she was the "strongest candidate on the economy".
Speaking on BBC Radio 4's Today programme, Mrs Mordaunt also dismissed the suggestion some of Mrs May's supporters could back Mr Gove in the next round of voting in an effort to prevent Mrs Leadsom's name being on the final shortlist of two presented to members.
"I would say to all my colleagues on Thursday, if you are voting for a candidate who you do not think is the best person to lead this country, you are doing something wrong," she said.
Despite her clear lead in the first round of voting by Tory MPs, Mrs May - who supported the campaign to stay in the EU - said she did not want the contest to be a "coronation".
"I have been clear from the start. The party and the country deserve an open, honest, robust debate - and the next leader needs to have won a mandate to lead.
"So there should be no deals, no tactical voting, and no coronation," she said.
Mrs Leadsom and Mr Gove both say the next PM must have campaigned for Leave.
Mrs May got 165 of 329 votes cast by Tory MPs on Tuesday. Mrs Leadsom came second with 66 and Mr Gove got 48.
'Matter of concern'
Given the margin of Mrs May's lead, she is almost certain to feature on the two-person ballot to be put to the around 150,000 Conservative members, with the eventual outcome due on 9 September.
But former Conservative chairman Grant Shapps called for the process to be accelerated, saying it should be finished by the end of July.
Mr Shapps has written to MPs seeking their backing, saying it was a "matter of concern for the country", and also plans a petition.
Mr Gove's supporters insist he can be trusted despite his dramatic 11th hour decision to turn on ally Boris Johnson and launch his own campaign.
Culture Minister Ed Vaizey told Today the U-turn had "caused Michael some difficulty" but said colleagues would "trust a man who was prepared to make that decision", claiming his was the campaign "building the momentum".