Saskatchewan's interim Opposition leader says former deputy premier Don McMorris must resign as an MLA now that he has a conviction for driving while impaired by alcohol.

Trent Wotherspoon says if Don McMorris does not step down, the premier should insist upon it.

Wotherspoon admits the NDP allowed candidates to run in the last election who also had impaired driving convictions, as did the Saskatchewan Party, but he says it's different when a sitting MLA does it.

"We have a code of conduct which requires us to be lawful, requires us to be held to a higher standard beyond that and regardless of all of that, drinking and driving is an issue and a problem all across our province and for him to continue as an MLA would send all the wrong signals to kids and communities across our province," Wotherspoon told reporters Monday at the provincial legislative building.

Premier Brad Wall said McMorris has not offered to resign as an MLA and he will not ask him to do so.

Wall says McMorris still has a lot to offer as a politician.

"When he goes through the process he's going through, gets the counselling he needs and makes the changes that he's making, I think he has much to offer the people of Indian Head-Milestone," Wall said.

He added everything that he has seen would indicate that McMorris' constituents agree with that assessment.