Canada's election watchdog says former finance minister Bill Morneau broke the law when he promoted Liberal candidates at events he attended while in charge of the finance portfolio.

The commissioner of Canada elections says before the last federal election, Morneau pumped up two prospective candidates who were attending separate events he headlined as finance minister.

One candidate, Anita Anand, has since gone on to become a cabinet minister herself.

Ministers aren't allowed to use taxpayer funds for partisan gain, but there are also provisions in election law that bar anyone but individuals from donating to campaigns.

That's the provision the commissioner says Morneau violated when he promoted the candidates, as government resources were used to the benefit of the Liberal party.

The commissioner says there is no indication Morneau had intended to use public resources for partisan purposes or that he was involved personally in planning the events in question.

Morneau's riding association has paid back the costs of the two events, and Morneau himself has been fined $300.