The federal government, attempting to resolve a serious diplomatic controversy with Canada, yesterday took the unprecedented step of asking Florida to parole a Canadian businessman convicted of land fraud after American bounty hunters allegedly kidnaped him in Toronto.

Secretary of State George P. Shultz told the Florida Parole Commission that the alleged 1981 kidnaping of Sidney L. Jaffe has "outraged" Canadian officials and has placed a "severe strain" on U.S.-Canadian relations.

"Canadian authorities have raised this matter in virtually every recent high-level contact between our two nations," Shultz said in a statement accompanying the parole request, filed by Attorney General William French Smith.

The action follows an equally extraordinary petition for Jaffe's release filed by the Canadian government last month in a federal court in Jacksonville.

The controversy now pits the highest levels of the U.S. and Canadian governments against a local prosecutor, Stephen L. Boyles.

"I guess they got their job and I got mine," Boyles said in a telephone interview yesterday.

Boyles filed new land-fraud charges against Jaffe on July 8 that could make Jaffe ineligible for parole, rendering yesterday's request irrelevant. Boyles said that he had heard rumors of the pending government parole request when he filed the new charges, but he said that was not the reason he acted.

Jaffe, a well-known businessman and patron of the arts in Canada, was charged in 1980 by Boyles' office in Jacksonville with selling improper land deeds. Bail was set at $137,000.

After Jaffe failed to appear for trial, an international bounty hunter hired by a Jacksonville bail company allegedly seized Jaffe as he was returning from an afternoon run in Toronto. He was returned to Florida, convicted and sentenced to 145 years in prison under numerous counts.

Ordinarily, international bail jumpers are sought under extradition treaties between the United States and foreign governments. Florida officials, who did not seek formal extradition, deny involvement in the abduction.

"It is perfectly understandable that the government of Canada is outraged," Shultz said.

"I wish to emphasize," he said in his message to the parole commission, "that Canada is our most important extradition treaty partner, and that the maintenance of the excellent extradition relationship we have had with Canada is greatly in the law enforcement interest of Florida and the other states, as well as of the federal government . . . .

"The Jaffe case threatens to have a generally deleterious effect on our relations with Canada," Shultz continued.

Axel Kleiboemer, a Washington lawyer representing Canada in efforts to have Jaffe released, said yesterday that the case "has absolutely nothing to do with Mr. Jaffe's guilt or innocence or with his citizenship. Canada has filed this suit a habeas corpus petition in order to vindicate its rights under the extradition treaties. The issue is whether or not lawlessness in international relations is going to be tolerated."

Brian Dickson, first secretary of the Canadian Embassy here, said that his government welcomed yesterday's action by Smith and Schultz. Both governments "realize that this is a bilateral issue which needs to be resolved," he said.