Candidates in Winnipeg's civic election called for an investigation — and whistleblower legislation for city workers — after the city fired one of its assessors for refusing to support tax information he didn't agree with while testifying at a Municipal Board hearing.

City assessor Larry Barthelett was fired in July after he told a tax hearing in April that he couldn't support his department's position on a case involving three properties owned by Maple Leaf Foods.

Barthelett testified that he believed the properties were worth far less than what city figures showed. The municipal board has yet to rule on that case.

The company could receive a property tax refund of up to $800,000, plus interest, if it gets a ruling in its favour.

The city decided Barthelett had compromised the employee-employer relationship and that his managers in the assessment department had lost trust in him.

Mayoral candidate Kaj Hasselriis called for a review of Barthelett's case by an arbitrator. He said Monday that Barthelett did the right thing when he refused to support a position he didn't believe in while under oath.

"The city worker is responsible to the people of Winnipeg," Hasselriis said. "What he saw here was an injustice happening against the citizens of Winnipeg."

Hasselriis said he's concerned about the greater impact of Barthelett's firing, adding it proves the city needs whistleblower legislation to protect its workers.

"This is the problem when people get fired. It sends a chill through not only a department, but through an entire bureaucracy. This is not the right example to be setting," he said.

Gary Swanson, president of Local 500 of the Canadian Union of Public Employees, which represents most city workers, also called for an investigation into the matter, especially because it involves a controversial issue like tax assessment.

"It's in the public interest to be sure that, in this type of work, that everything is above board," Swanson said.

The city, for its part, may have to answer to the province's attorney general on the matter. The Municipal Board has since been asked to have the attorney general investigate the city assessment department. A decision on that isn't expected for at least another month.