Labour leader Sir Keir Starmer is under investigation by the UK's parliamentary commissioner for standards Kathryn Stone over potential breaches of rules on earnings and gifts.
Parliament's website showed on Monday that Ms Stone is looking at whether the opposition leader broke two sections of the MPs' code of conduct on registering interests.
The alleged breaches relate to several failures to register gifts from football teams, donations to staff from the Just Eat food delivery firm, and book royalties worth thousands of pounds within 28 days of receipt, a Labour source said.
One strand of Ms Stone’s investigation, which began last Wednesday, is looking at the registration of interests under the section on employment and earnings.
A second area being looked at is a possible breach of the section concerning gifts, benefits and hospitality from UK sources.
During a campaign visit to Wakefield in West Yorkshire on Monday, before a local by-election, the Labour leader said the allegations did not come as a surprise.
“My office is dealing with it and will be replying in due course,” he said.
Asked if he is sure he has done nothing wrong, he replied: “Absolutely confident; there’s no problem here.”
Sir Keir apologised to Ms Stone “for the fact that administrative errors in his office have led to a small number of late declarations”, his spokesman said.
The opposition leader received an £18,450 advance from publisher HarperCollins in April for a book he is writing in which he is expected to set out his vision for Britain.
The sum, which he has pledged to donate to charitable causes, appeared to have been declared a day late, while royalties for two legal books published before the former lawyer became an MP were also delayed.
A second area being looked at is a possible breach of the section concerning gifts, benefits and hospitality from UK sources.
Sir Keir received a directors’ box for two people at Crystal Palace worth £720, when they beat Arsenal 3-0 on April 4. It was not registered until May 5.
He received four tickets for Watford vs Arsenal, worth a total of £1,416, for their March 6 match. The gift was registered on May 6.
The register shows Just Eat gave tickets to Labour staff for the Taste of London festival and the British Kebab awards.
Sir Keir’s spokesman said “we are happy to provide” additional information that has been requested by Ms Stone.
“Keir Starmer takes his declaration responsibilities very seriously and has already apologised for the fact that administrative errors in his office have led to a small number of late declarations,” the spokesman added.
The donations from the company exceeded the £300 limit for registration on October 29, but were not declared until December 23.
Durham Police in May announced an investigation into allegations that Mr Starmer broke Covid-19 lockdown rules.
Officers are examining footage showing him drinking alcohol with Labour Party members at a gathering during their campaign for the Hartlepool by-election in April last year.
