Jeremy Hunt is facing a Parliamentary inquiry into claims that he failed to register thousands of pounds worth of corporate hospitality from media firms.
Parliamentary standards commissioner John Lyon confirmed that he had initiated an investigation into the Culture Secretary in response to a complaint from the Labour MP Stephen McCabe.
The move comes just days before Mr Hunt’s former special advisor Adam Smith is due to give evidence to the Leveson Inquiry.
Mr Smith will appear on Thursday to face difficult questions about his “inappropriate” contacts News Corp during its bid for BSkyB. Crucially, under oath, he will have to explain the extent to which Mr Hunt knew about those contacts.
Mr Hunt is expected to give his own evidence to Leveson in the next few weeks.
The latest problems facing the Culture Secretary arose after Mr McCabe wrote to the Standards Commissioner raising concerns about a series of “networking events” involving eight organisations which Ed Vaizey, Mr Hunt’s deputy said they had both attended while in opposition.
Although Mr Vaizey recorded the events in the register of interests as donations in kind worth a total of around £27,000, Mr Hunt did not mention them in his own entry in the register.
Mr Vaizey stated that they attended the events between July 2009 and March 2010 which were described as ‘networking event(s) to enable the Conservative frontbench team (Ed Vaizey and Jeremy Hunt) to meet sector leaders from the arts and creative industries’.
Mr Vaizey declared that Mr Hunt was present all eight events, including one hosted by BSkyB on 7 October 2009, which cost £3,800.
The Culture Secretary said he would amend his entry in the Register of Interests to show that he took a donation worth £1,473.81 from advertising agency DDB UK in September 2009, another worth £1,435 from London media hangout the Groucho Club and a third in July that year from M&C Saatchi, the advertising firm set up by Tory donor and Conservative peer Lord Saatchi. That event cost £4,563.50 – a total of £7472.31.
However Mr Hunt denied he had attended five other meetings including the one paid for by BSkyB.
The Parliamentary Code of Conduct states that ‘it is the responsibility of Members to notify changes in their registrable interests within four weeks of each change occurring’.
Mr Lyon's office confirmed that an inquiry had been launched but refused to comment further.
The investigation could take as long as a year to complete and if Sir John finds Mr Hunt broke the rules, a committee of MPs will decide on any sanctions. Punishments can include being forced to apologise to MPs in the House of Commons.
A spokesman for Mr Hunt said: “As soon as we realised there was a mistake we amended the register. We will cooperate fully with any lines of inquiry.”
In another development MPs will debate the findings of the select committee report into phone hacking today.
The Culture, Media and Sport Select Committee accused News of the World editor Colin Myler, the paper's former legal manager Tom Crone and former News International chairman Les Hinton of misleading it in their evidence.
Mr Bercow gave permission for committee chairman John Whittingdale to table a motion for debate tomorrow, which could pave the way for parliamentary sanctions against the three.