Home Secretary Sajid Javid has said his exclusion from the state banquet held for the US President was “odd”.
Several other ministers, including Environment Secretary Michael Gove and Defence Secretary Penny Mordaunt, attended the event earlier this month.
Mr Javid criticised Donald Trump when he shared tweets from far-right group Britain First in 2017.
The PM’s spokesman said places were limited and it was not appropriate to comment about who asked to attend.
“A large number of ministers who requested to attend who were not able to do so,” he said.
The spokesman added: “The prime minister is proud to have appointed Sajid Javid as the country’s first Muslim home secretary.”
Speaking to BBC Radio 4’s Today programme, Mr Javid said: “I don’t like it. It is odd.”
“My office did ask Number 10 [for a reason] and they said ‘No’.”
Asked if he thought his exclusion was due to his Muslim background, Mr Javid said: “I am not saying that at all. I really don’t know.”
He said he was told by Number 10 that “normally” invitations “don’t always” go to home secretaries.
But former Home Secretary Jacqui Smith, who became the first woman to hold the post in 2007, said she attended state banquets in her role.
BBC political correspondent Ross Hawkins said Amber Rudd attended a state banquet for the King of Spain in 2017 in her capacity as home secretary.
However, Mrs May, in her previous role of home secretary, did not attend the state banquet for then-US president Barack Obama in 2011.
There is a fixed list for government places at state banquets, which includes but is not limited to the prime minister, the foreign secretary and the chancellor. The position of home secretary is not on that list.
In a Twitter clash with Mr Trump in 2017, Mr Javid criticised the president for re-tweeting a tweet from the far-right organisation Britain First.
He said the president had endorsed a “vile hate-filled organisation that hates me and people like me”.
The Secretary General of the Muslim Council of Britain (MCB) wrote to Theresa May last week asking for an explanation for Mr Javid’s exclusion.
In his letter, Harun Rashid Khan wrote: “There are fears that our nation is willing to give up on our principles of fairness and equality for all, in order to placate President Trump.”
The MCB is an umbrella organisation of various UK Muslim bodies, including mosques, schools, and charitable associations.
Other politicians including Labour leader Jeremy Corbyn, Commons Speaker John Bercow, Lib Dems Leader Sir Vince Cable and SNP Westminster leader Ian Blackford refused an invitation to attend the banquet at Buckingham Palace.
Mr Corbyn, who later joined the protest against Mr Trump, argued it would be wrong to “roll out the red carpet” for the US president, whom he accused of using “racist and misogynist rhetoric”.