EDMONTON -- United Conservative Leader Jason Kenney says his party is investigating allegations of fraud and bribery in a nomination race in Calgary.

Kenney declined to discuss the issue further, saying he doesn't want to compromise the review into the race that selected Peter Singh as the party's candidate for Calgary East on Nov. 3.

Four losing candidates have since said Singh won by offering gifts to voters and signing up people as party members without their consent.

Singh has denied the allegations.

Calls to his place of business were not returned and his phone's mailbox was full.

NDP deputy premier Sarah Hoffman says the investigation should go to the police, given it's alleged that people's credit card numbers were used without their knowledge to purchase UCP memberships.

Kenney says it should be noted that his party has had 68 nomination races and only four have involved accusations of malfeasance or controversy.

"We obviously take seriously any allegations of wrongdoing, so there will be a fair investigation into that particular instance," Kenney said Thursday.

"Inevitably when you have hotly contested nominations, there are going to be in some cases complaints about the process."

Hoffman disagreed.

"If somebody were using credit card information that wasn't granted to do so in purchasing things, that certainly sounds like allegations of fraud and I don't think an internal party process is appropriate," she said.

"I think the UCP should be referring this to police."