Sam Hamad has stepped aside from his cabinet positions pending an ethics investigation into his relationship with a political fundraiser who is facing criminal charges.

Premier Philippe Couillard said Hamad himself offered to give up his role as Treasury Board president, as well as several minor portfolios. On Friday Hamad requested the ethics commissioner probe his ties with Marc-Yvan Côté.

Couillard described Hamad's decision as "noble."

"I trust Sam Hamad. My trust in him has not been diminished by the events of the past days," Couillard told reporters in Montreal. He made the announcement just moments after attending a "national" funeral for Claire Kirkland-Casgrain.

Quebec Finance Minister Carlos Leitao and Labour Minister François Blais will temporarily take over Hamad's duties.

The Liberal government issued a statement Saturday night, announcing Leitao will oversee the Treasury Board, while Blais will be responsible for Hamad's riding.

Philippe Couillard makes announcement on Sam Hamad <a href="https://t.co/Tg3rz9JdV6">pic.twitter.com/Tg3rz9JdV6</a> —@jbernstien

Hamad has been at the centre of controversy since a Radio-Canada program earlier this week revealed that he exchanged a series of emails with Côté between 2008 and 2012. Hamad was the minister of labour and then economic development in the Charest Liberal government at the time.

Côté was arrested last month, alongside former Liberal deputy premier Nathalie Normandeau, on corruption and fraud charges.

Up until his arrest, Côté was the vice-chairman of the board at the firm Premier Tech. In the emails obtained by Radio-Canada, it appears that Hamad sought to support the company's interests within the government.

It also appears that ​Côté received strategic information about government decisions from Hamad. Côté and his family made a large series of donations — close to $17,000 — to the Liberals during the period of the email exchange.

Hamad denies that the emails, or the Radio-Canada report, demonstrate any wrongdoing on his part.

« On attaque injustement mon intégrité. Je répète que je n'ai rien à me reprocher et que je n'ai fait que mon... <a href="https://t.co/9Gz1jw2tYt">https://t.co/9Gz1jw2tYt</a> —@SamHamad

"My reputation is being attacked unjustly," Hamad said in a news release on Saturday. "I repeat, I have done nothing wrong."

Hamad's resignation is likely to complicate Couillard's efforts to distance himself from the ethical concerns about the previous Liberal government raised by Normandeau's arrest.

The premier has stressed that the Quebec Liberal Party has changed its fundraising policies since the Charest era.

But opposition parties seized on Hamad's resignation to demand more transparency from the Liberals.

"What we should ask is that the premier be able to explain to the population ... how this party is financed," Parti Québécois Leader Pierre Karl Péladeau said.

Pierre Karl Peladeau reacts to announcement that <a href="https://twitter.com/hashtag/SamHamad?src=hash">#SamHamad</a> will temporarily step aside <a href="https://t.co/JAOgth680m">pic.twitter.com/JAOgth680m</a> —@jbernstien

The PQ's Bernard Drainville also called for Hamad to step down from the Liberal caucus entirely.

<a href="https://twitter.com/hashtag/SamHamad?src=hash">#SamHamad</a> doit également se retirer du caucus du PLQ. PCouillard a donc bien de la misère à rompre av l'héritage de Jean Charest!! <a href="https://twitter.com/hashtag/PolQc?src=hash">#PolQc</a> /2 —@BDrainvillePQ

Françoise David, Québec Solidaire MNA and co-spokesperson, wants Couillard to investigate his ministers' behaviour more closely.

"I think the decision is the beginning of a series of good decisions," David said. "But it has go much further than that."