REGINA - Convicted killer Colin Thatcher says a Saskatchewan law that could stop him from collecting profits from his book is "an over-reaction, tantamount to smashing an ant with a sledgehammer."

The provincial government is trying to seize the money under the law that was quickly passed earlier this year to stop criminals from benefiting financially if they sell their stories.

Thatcher, who represented himself during a brief appearance Thursday before a judge in Regina, intends to argue that the law is unconstitutional.

"My Lord, obviously, you can appreciate this is very uncharted territory for me," Thatcher told Court of Queen's Bench Justice Ted Zarzeczny.

"I have come to the conclusion that the question of whether my book falls within the act is going to raise some constitutional questions. I don't care to make them anymore complicated than necessary, but I think in my arguments I must use some references to the charter," he said.

"My arguments will be quite simple and quite basic."

The matter was adjourned for a hearing Dec. 3 to give both sides time to prepare. Notice must also be given to the federal government under the Constitutional Questions Act.

Thatcher refused to comment on his way in or out of the courthouse.

But in documents filed with the court he wrote: "This matter only exists because I wrote a book the government does not like.

"In response, the government seeks to punish me with retroactive legislation that financially penalizes me for writing something of which they disapprove."

Thatcher said that government officials were aware of his intention to publish the book for more than two years, but did nothing to intervene until last spring.

Saskatchewan Justice Minister Don Morgan introduced the Profits of Criminal Notoriety Act in May when the pending book prompted public discussion and debate about whether the province needed to act.

"When it suited their purpose, they stepped in with retroactive legislation, citing a public outcry after a bad day in question period and a newspaper editorial," wrote Thatcher.

"Free speech is too important to tinker with without abundant cause. I beg you to allow the marketplace to do the regulating."

The former Saskatchewan cabinet minister has repeatedly argued that the law doesn't apply to his book "Final Appeal: Anatomy of a Frame." Thatcher says the book is about his dealings with the justice system and does not recount the 1983 murder of his former wife, JoAnn Wilson.

Wilson was bludgeoned and shot in the garage of her Regina home, just steps away from the Saskatchewan legislature.

Thatcher spent 22 years behind bars. He was released on parole in 2006 and now lives on the family ranch near Moose Jaw, Sask.

Darryl Brown, the Crown lawyer for the Saskatchewan government, said Thursday it's an important case.

"It will test the boundaries of freedom of expression and things like that so I think it's significant," Brown said outside the courthouse.

Brown added he's confident the law is "constitutionally sound."

Four other provinces have similar legislation but this is the first time such a law has been challenged, he said.

"It will be precedent-setting. I can't say how far-reaching. There are other provinces with the same statute, so it will potentially have an impact on those."