Alberta Premier Alison Redford says she was disgusted to learn one of her former MLAs was arrested in a prostitution sting while in St. Paul Minnesota while on government business.

"I was shocked and disappointed to see that conduct," she told reporters Thursday morning at a premier's breakfast at the Alberta Legislature. "It's not at all the standard of conduct that I expect from anyone in our caucus.

"I was disgusted by it."

Mike Allen, the MLA for Fort McMurray-Wood Buffalo, was arrested Monday for allegedly answering an ad for escort services that was placed by undercover police officers in St. Paul.

Prostitution is an especially sensitive issue for her, Redford said. 

"When I was justice minister we started doing work with respect to sexual exploitation of women and human trafficking," she said. "This is an issue that is very close to my heart".

Redford told reporters that Allen repaid his expenses for the business trip.

"As soon as I heard that this had happened I asked for that and I understand he has issued a cheque for all the expenses that (were) appropriate," she said.

Allen resigned from the Progressive Conservative caucus on Tuesday and will sit in the legislature as an independent.

When asked if Allen would be welcomed back if no charges are laid, Redford would only say, "I am very troubled by that."

Members of Allen's constituency association will meet to decide what happens next.

"He's going to need to take some time to reflect on what it is that led him down the road and the path he took," said Jeffrey Cromwell from the Fort McMurray Progressive Conservative Riding Association.

"He's going to have to have a serious discussion with the constituents about his ability to continue to effectively represent them in the Alberta legislature."

Officials in St. Paul, Minnesota will decide in the next few days whether Allen will be formally charged with soliciting for prostitution.