WINNIPEG -- The union representing city employees has sent a letter to Winnipeg's mayor and council alleging inaction over complaints of racism, bullying, and harassment that has led to a 'toxic workplace'.

Gord Delbridge, the president of CUPE Local 500, said they have filed grievances against the City of Winnipeg over human rights issues and respectful workplace concerns.

"We are concerned that city administration is unable or unwilling to deal with allegations of human rights issues, including complaints of racism, bullying, and harassment," Delbridge said in a written statement posted online.

"These complaints take months to get an initial investigation meeting, and are seemingly never resolved, leading to festering toxic workplace issues and continued victimization of employees who have raised these concerns."

In an interview with CTV News, Delbridge said he was not able to give specific examples or provide further details on the allegations, citing privacy concerns as well as ongoing grievances filed against the city.

"It's just gotten to a point of a level of frustration where it is not being handled in a manner that is fair to the individuals that are being impacted by these human rights violations and workplace complaints," he told CTV News.

Delbridge said the union has also filed grievances against the city for awarding "multi-million dollar contracts" to outsourced businesses without consultation or oversight – something he said is against the city's collective agreement with the union.

During a news conference on Friday, Mayor Brian Bowman said he reviewed the letter after hearing about it from media.

"Some of the concerns that they raised need to be taken very seriously and properly investigated," he said.

Bowman said he has reached out to the city's CAO about the concerns, and said he has been advised the city will be contacting the union.

"I communicated to him that there would be a desire amongst all members of council, myself included, to get an update as soon as possible so that we can determine what, if any, steps are needed at the political level."

A spokesperson for the City of Winnipeg told CTV News that they have received the letter and will be "carefully reviewing the details of the concerns raised by CUPE."

Delbridge said he hopes the pressure will lead to change.

"We're hoping that there may be a reform to the policy, that there is going to be some action taken," he said. "We are more than willing to sit down and meet with the city, but ultimately often these claims and issues arise just out of a lack of leadership, and we're hoping that there is some pressure as a result of this letter."

He said several city councillors along with some senior city administration have reached out to him regarding the concerns.