Angela Rayner has said she did not break any rules over her “personal holiday” in New York with Sam Tarry, for which the pair stayed at the flat of Labour donor Lord Waheed Alli.
The deputy prime minister stayed with her then partner Mr Tarry, a former Labour MP, at the $2.5m Manhattan penthouse over New Year, according to the Sunday Times.
She did not previously report that Mr Tarry had stayed with her.
Labour has been dogged with allegations of cronyism in the lead up to their conference after it was reported Lord Alli had given substantial gifts to party leaders.
Prime minister Sir Keir Starmer and chancellor Rachel Reeves have both said they will no longer accept donations for clothes, as has Ms Rayner.
She told the BBC’s Sunday with Laura Kuenssberg: “I was on holiday in New York, I paid for my holiday in New York but, as friends do, a friend allowed me to stay.
“I often allow people to stay at mine. I went beyond the rules because that person had donated to my deputy leadership [campaign], who happens to be a friend, but is a politician in their own right.”
The pair, who have now broken up, are said to have stayed for five days at the flat from December 29 to January 2.
Mr Tarry, who was MP for Ilford South but did not stand at the last election, paid for his own flight but did stay at the house for free - it is understood.
Ms Rayner added: “That person [Tarry] went to New York and I met up with them and I met up with a number of friends while I was in New York.
“It was a personal holiday and I think I followed the rules, in fact I went above that, and I wanted to do that to be transparent about this.
"I don't believe I broke any rules.
"I had the use of the apartment and I disclosed that I had the use of the apartment.”
She said that she accepted the “frustration” of some but said donations are necessary for candidates to run for election.
“I get that people are frustrated, in particular the circumstances that we’re in, but donations or gifts and hospitality and monetary donations have been a feature of our politics for a very long time,” she added.
She added that Lord Alli received “nothing” in return for his donation. "I promised nothing and gave him nothing in return,” Ms Rayner added.
A Conservative spokesman offered: “Not only has Rayner been living the high life with a free holiday paid for by a donor it appears she has breached the rules by failing to be transparent with her declaration.”
