Prime Minister Justin Trudeau defended his mother's trip to Washington for the recent state dinner Monday, saying President Barack Obama personally invited her to attend the lavish fete.

A total of 44 people — including the parents of the prime minister's wife, Sophie Grégoire-Trudeau — were part of the delegation that travelled to D.C. at a cost of some $25,000. Other invoices and expense claims from the trip are still left to be counted.

A spokesman from the prime minister's office contacted CBC News Monday to say while the delegation flew at the expense of the Department of National Defence — on a government aircraft — the travel cost for family members would be repaid to taxpayers based on a market-priced ticket for a comparable flight at a later date, he said. The family members stayed in Washington as guests of the White House, he added.

"It was the president himself who personally invited my mother and my in-laws," Trudeau said in French during a press conference Monday.

"[The president] highlighted the presence of my mother during the dinner to congratulate her for the work she's been doing in the area of mental health for many years."

The Conservative opposition jumped on the trip's price tag in question period Monday, asking why the prime minister needed to travel with a "massive, celebrity-sized entourage."

"We all know that our relationship with the U.S. is important, and that high-level visits are beneficial, and we know there are important issues to discuss like, perhaps, the energy sector, but what we can't figure out is what expertise the prime minister's in-laws have and why he couldn't find room for [Jim Carr], the natural resources minister," Conservative MP Andrew Scheer asked.

House Leader Dominic LeBlanc defended the guest list, adding it was the first time Canada has been honoured with a state dinner in nearly 20 years.

He said that Trudeau's in-laws were also personally invited by Obama, but offered no reason as to why Carr was not part of the delegation that included nine other cabinet ministers.

'Rapprochement' with the United States

Trudeau said Monday the trip was part of his government's efforts to bolster relations with what he has called Canada's most important international ally. He said the dinner was a positive moment for all Canadians, as it represented a "significant and concrete rapprochement with the United States," after 10 years of Stephen Harper's government.

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President Obama makes a toast for the Prime Minister Justin Trudeau and his wife, Sophie Gregoire-Trudeau, during a state dinner at the White House in Washington, March 10. (Joshua Roberts/Reuters)

Obama did in fact single out the prime minister's mother during the dinner, noting she personified the welcoming nature of Canadians.

"We also see Canada's spirit in your mother's brave advocacy for mental health care — and I want to give a special welcome to Margaret Trudeau tonight," Obama said during his toast.

The prime minister's mother went public with her battle with bipolar disorder in 2006 and penned an autobiography, Changing My Mind, which detailed her struggle with the disease. She has since delivered hundreds of speeches across North America in an effort to reduce the stigma around mental illness.

Obama also celebrated Trudeau's wife, Sophie Gregoire-Trudeau, in the same breath. "We see Canada's spirit in Sophie — a champion of women and girls, because our daughters deserve the same opportunities that anybody's sons do."

Liberal 'bagman' also at state dinner

The Liberal Party's national president, Anna Gainey, and chief Liberal fundraiser Stephen Bronfman, were also in attendance for the lavish White House dinner.

The Conservatives' Scheer said Canadians were "disgusted" to know these two people — who are also known to be close personal friends of the prime minister — were "along for the ride."

Anna Gainey at the Liberal Convention

Liberal Party president Anna Gainey was in attendance at state dinner in Washington in March. House Leader Dominic LeBlanc said Monday she personally paid for all expenses she incurred as part of the trip. (Ryan Remiorz/Canadian Press)

"The prime minister's political friends were granted unprecedented access to senior U.S. officials. The prime minister used the state visit to help his buddies connect with Washington insiders for their own personal gain. This was clearly a reward for their political support," Scheer said.

LeBlanc batted the question away, saying that they too were invited to attend the event by the White House.

"[Scheer] should also know that the taxpayers, in no way, contributed to the expenses of these individuals. All of their expenses, at all times, were incurred by them personally and the taxpayers, in no way, directly or indirectly, contributed to this part of the visit," he said.


Follow John Paul Tasker on Twitter @JPTasker

With files from the Canadian Press