OTTAWA -- Justin Trudeau is defending the size of the delegation that accompanied him during his first visit to Washington last March, revealing that at least three of them -- his mother and his in-laws -- were personally invited by U.S. President Barack Obama.

But Canadian taxpayers apparently still footed the bill for the prime minister's family members.

A document tabled in the House of Commons last week disclosed that 44 people were part of the delegation, at a preliminary cost of just over $25,000, with some invoices and expense claims still to be tallied.

However, the Washington entourage pales by comparison to the enormous delegation that attended the two-week United Nations climate change summit in Paris last December.

According to a new document tabled in the Commons, 121 people attended some or all of the summit, including Trudeau who spent several days in Paris.

The total cost of transporting the delegation by government aircraft is estimated at $188,700. Accommodation, meals and other expenses are not included in the document, which was tabled in response to a written question from Conservative MP Ed Fast, who was himself a member of the Paris delegation.

"This government went to Paris to build a lasting solution to the challenge of climate change and the agreement (reached) puts the world on the right path," the document says.

"To achieve real change on this issue, a collaborative and inclusive approach is required. That's why the Canadian delegation to the Paris climate conference (COP21) included representatives from provinces and territories, national aboriginal organizations, youth, non-governmental organizations, businesses and opposition members of Parliament."

The document lists the name of each delegation member and the duration of his or her stay but not the cost for each individual. That prompted Fast to accuse the government Monday of having something to hide.

The first time he asked about the climate change delegation, Fast said he was given a list of expenses racked up by each delegation member but no names were provided. This time, he said he's got the names but no individual expenses.

Moreover, Fast said the latest document includes 24 fewer delegates than the initial response he received from the government.

"Canadians smell something fishy. What is the government hiding?" he demanded in the Commons.

Trudeau, meanwhile, defended the size and expense of the Washington delegation, arguing that the three-day visit marked the first time in almost 20 years that a president threw a state dinner in honour of a Canadian prime minister.

He said the size of the delegation was meant to underscore his long-standing view that there is no more important international relationship for Canada than its unique connection with the United States.

Trudeau noted that Obama praised his mother, Margaret Trudeau, during the state dinner for her work on mental health issues. And he called that a "very positive moment" that signalled a rapprochement in Canada-U.S. relations after a chilly period under his Conservative predecessor, Stephen Harper.

A spokesman for the Prime Minister's Office said Trudeau's mother and in-laws travelled to Washington on a government jet and would repay the cost based on the commercial value of the flight.

During his three days in the U.S. capital, Trudeau was accompanied by at least nine cabinet ministers and a bevy of senior staffers from the Prime Minister's Office, as well as Liberal party president Anna Gainey and Liberal chief fundraiser Stephen Bronfman.

The party said last week that none of the expenses incurred by Gainey and Bronfman was paid for by taxpayers.