Justin Tang/CP Prime Minister Justin Trudeau passes members of the Ceremonial Guard as he arrives for a press conference following a swearing in ceremony at Rideau Hall in Ottawa on July 18, 2018.

Brison announced Thursday morning that he won't seek re-election this fall because he wants to spend more time with his family. He'll said he'll quit the cabinet before then because the government is best served by ministers who are running again.

OTTAWA — Prime Minister Justin Trudeau will shuffle his cabinet Monday to deal with the resignation of Treasury Board President Scott Brison, he said in a news conference Thursday.

Trudeau said he respects Brison's decision to leave to spend time with his young twin daughters.

"Obviously this will require some changes to our cabinet, and that's something that we're going to be announcing on Monday," he said to reporters during a tour of a new building at Thompson Rivers University in Kamloops, B.C.

Trudeau refused to be drawn on whether he plans a small shuffle just to replace Brison or a larger one with multiple ministers changing portfolios.

As president of the Treasury Board (and the minister responsible for digital government), Brison has had responsibilities for minding the public purse and overseeing the federal public service. The portfolio isn't flashy but can cause big headaches for a government if it's mishandled.

"His thoughtfulness, his capacity to understand how best to deliver programming, his ability to understand Canadians through his many, many years of service was extremely valuable around the cabinet table," Trudeau said.

Brison has been the face of the Liberal government in Nova Scotia, where the party won every seat in 2015. But he's also been close to the story of Vice-Admiral Mark Norman, who is facing a trial for breach of trust related to allegations he leaked secrets to promote a navy shipbuilding contract. Norman's case is to go to trial late this summer, just as the campaign for the Oct. 21 election is getting underway.

Vice-admiral's court case in focus

Brison has been accused of pressuring the newly-minted Trudeau government in 2015 to suspend a $700-million plan to build a new supply ship, a move that the RCMP alleges prompted Norman to leak secrets to Quebec's Davie Shipbuilding so it could pressure the Liberals into restarting the project.

Brison has told the House of Commons that he simply did his job as Treasury Board president, the minder of the public purse, to ensure taxpayers were getting good value for the ship contract.

Brison has denied accusations levelled by Norman's lawyers and echoed by opposition MPs that he lobbied on behalf of Halifax-based Irving Shipbuilding, which wanted the Liberals to cancel the Davie deal and hire Irving for the supply-ship job instead.

Earlier: Scheer presses Trudeau on Mark Norman