NDP Leader Jagmeet Singh says the inclusion of Gerald Butts in the Liberal re-election effort is another sign that the governing party puts its friends first.

"It's disappointing," Singh said Sunday in an interview on CTV News Channel.

"It again just perpetuates the same fear that people had that this is a Liberal Party and a Liberal government … who are making their decisions based on very questionable priorities."

Butts, a longtime close friend of Prime Minister Justin Trudeau's, resigned in February from his role as Trudeau's principal secretary.

His resignation came amid allegations that he improperly pressured then-attorney general Jody Wilson-Raybould into handling corruption and fraud charges against engineering giant SNC-Lavalin through a remediation agreement instead of a criminal prosecution.

Butts has denied any wrongdoing in the matter and has said nothing that happened regarding SNC-Lavalin went beyond the normal course of government operations. He said he was resigning because it was "in the best interests of the office and its important work" for him to do so.

Sources confirmed to CTV News on Saturday that Butts is expected to advise Prime Minister Justin Trudeau and other senior Liberals during the federal election campaign. Liberal strategist Jonathan Scott told CTV News Channel on Saturday that he doesn't think the backgrounds of campaign staff will matter to voters.

Conservatives have railed against the news, with MP Pierre Pollievere telling CTV News that Butts' role in the campaign meant his resignation "was just a big phony act to cover for the boss."

Singh added his voice to the chorus on Sunday, saying that giving Butts a role in the campaign displayed "a certain arrogance" toward Canadians.

"They seem to jump anytime a powerful interest group or their close friends ask them to do things, and seem to delay whenever everyday folks and families need help," he said.

The interview with the NDP leader also touched on issues including pipelines, energy policy and health care.