Michael Gove is under investigation by Parliament’s standards watchdog, it was revealed on Thursday.
The probe relates to the Housing Secretary's register of financial interests.
The details of investigations by the Standards Commissioner, Daniel Greenberg, are kept confidential until the inquiry is concluded and those under investigation are barred from discussing the allegations.
It comes after reports that Mr Gove failed to register VIP hospitality he enjoyed at a football match with a Conservative donor whose firm he had recommended for multimillion-pound personal protective equipment (PPE) contracts during the Covid-19 pandemic.
He was entertained at a Queens Park Rangers match in 2021 with David Meller, whose company Meller Designs was awarded six PPE contracts worth £164 million following the then-Cabinet Office minister's referral in 2020, according to the Guardian.
Mr Gove said his failure to declare the two complimentary tickets he received was an "oversight" and that he had written to parliamentary authorities to inform them of the potential omission.
A code of conduct requires MPs to register gifts, benefits and hospitality over a value of £300.
The senior Tory is one of six Conservative MPs currently being investigated by the Standards Commissioner.
These include Deputy Speaker Dame Eleanor Laing, Sir Bernard Jenkin and Virginia Crosbie, who are believed to be under investigation for allegedly attending a birthday drinks event during the pandemic in breach of lockdown rules.
The Metropolitan Police closed their investigation into the same allegations in December with no action being taken.
Other Conservative MPs under investigation include Bob Stewart and Miriam Cates, who is facing claims that she caused "significant damage to the reputation of the House as a whole, or of its members generally".
