Prime Minister Justin Trudeau’s chief representative in the Senate is set to name a deputy leader and whip to handle independent senators, sources say.

Senate insiders say Senator Peter Harder, the Government Representative and de facto Senate Leader, will name Diane Bellemare as his deputy and Grant Mitchell as the whip.

The announcement is expected Wednesday.

Ms. Bellemare was named to the Senate in 2012 as a Conservative by then-prime mi‎nister Stephen Harper.

She announced in March that she was leaving the Tories to sit as an independent because she was motivated by a desire to restore the Red Chamber’s political relevance. She said she hoped to organize independent senators to give them more voice in the Senate.

Mr. Mitchell is a long-time Liberal with a reputation for being ultra-partisan against the Conservatives. He announced Monday he was leaving the independent Liberal caucus to sit as an independent.

‎Attempts to reach Senators Bellemare and Mitchell were unsuccessful but several well-placed Senate sources confirmed the two will be given leadership roles under Mr. Harder.

Mr. Harder, a former senior civil servant who headed Mr. Trudeau’s transition team, has been seeking an $800,000 office budget from the Senate internal economy committee, which is run by the Conservatives and independent Liberals.

The committee increased his budget by $400,000 from $250,000. Mr. Harder has been seeking to gain influence in the chamber for independent senators but has faced a backlash from the Conservatives and Liberal senators, who were banned from the Trudeau Liberal caucus before the last election.

The Liberals campaigned on making the institution less partisan and a more transparent body.