A legal battle is brewing over Alberta's new, tough drunk-driving laws.

The paperwork initiating a constitutional challenge is expected to be filed this week at the Edmonton Law Courts.

The law immediately suspends the licence of anyone charged with blowing over .08, which presumes that a person is guilty before they can be proven innocent, said lead lawyer Fred Kozak.

Some cases may take as long as 18 months to get to court, and Kozak suggests a number of people are pleading guilty just to get their license back sooner.

"Nobody would argue with the fact that impaired driving is a serious social issue," said Kozak. "We should be doing everything that we can to reduce the incidence of that. But you shouldn't trample on people's constitutional rights to do it."

Alberta Justice Minister Jonathan Denis said that he's "fully confident" the legislation will hold up in court.

"If people don't want to risk that type of a penalty, don't drink and drive," he said.