Jewish groups have accused the Canadian government of complicity in harbouring scores, perhaps hundreds, of alleged Nazi war criminals and time is running out to bring them to justice.

Canadian Jewish Congress (CJC) assistant counsel Steve Shulman said ''the sands of time have run out'' for prosecuting many alleged war criminals in Canada because of the country's reluctance until recent years to pursue them.

He cited the case of a 90-year-old Lithuanian man, Antanas Kenstavicius. It took Canada 48 years to launch a case against him for allegedly supervising units involved in the massacre of thousands of Jews in the Second World War.

Kenstavicius died on Jan. 22, the very day deportation hearings began against him, and with him perished any hope Jewish groups had of justice in his case. ''Here is a fellow that the RCMP (Royal Canadian Mounted Police) was informed of in 1948 by the Canadian Jewish Congress,'' Shulman said.

Justice Minister Allan Rock, sensitive to media coverage on the issue, said on Monday that by April the government would have started 12 cases against alleged war criminals. Ten have already begun, he said.

''We are determined to deny safe haven in Canada to war criminals,'' he said in a statement.

Canada has deported or extradited two alleged Nazi war criminals. The United States has stripped 57 Nazi ''persecutors'' of citizenship and deported 48 since 1979 when the Justice Department's Nazi-hunting Office of Special Investigations was created.

''Canada ... can certainly go some way to at least dulling the stain on its record by proceeding with expedition against as many war criminals as possible,'' Shulman said.

American detective Steven Rambam volunteered to investigate war crimes in Canada. Working from a list of 1,000 names, his team located 157 people, tried to interview 62 and actually spoke to 58 of them. He told Reuters by telephone from Israel he believed there were could be thousands more.

''I think what's remarkable is... it was so ... easy. We found, frankly, a third of them by looking in the phone book ... They knew they had nothing to fear by revealing their past and their affiliations and in many cases the specifics of their crime,'' he said. ''The other significant question that should arise from our success is why... didn't anybody do it 20 years ago?''

Rambam said he found it an absolute mystery the Canadian people had allowed their government to dally on the issue. ''They're politically motivated serial killers,'' he said of the former Nazis.

The CJC's Shulman said then-Prime Minister Pierre Trudeau had explained his unwillingness to push hard on war crimes by saying he did not want to exacerbate ethnic tensions. Trudeau did not did not return a phone call from Reuters for comment.

John Sims, the supervisor of Canada's war crimes unit, said Ottawa had put big resources into the hunt in the past decade under both Conservative former Prime Minister Brian Mulroney and Liberal Prime Minister Jean Chretien.

''While we can't rewrite history what we can do is try to bring to justice now the people who did heinous things with the Nazi war machine, and that's what we're committed to doing, and we're making significant progress,'' Sims said.

During his investigation, Jewish volunteer Rambam used the name Romano and said he was doing doctoral research for the fictitious St.Paul's University of the Americas in Belize. He said when he or his colleagues tracked down a suspect one of them would go to the door armed with secret recorders and transmitters hidden in a pen or a tie clip.

Some of the most graphic confessions came from Kenstavicius, who described the roundup of thousands of Lithuanian Jews who were stripped naked and mowed down into a purpose-built trench.

''Ten guys stay (stand) on the ditch, and then coming the commander, 'Bang,' and they fall down. Some time, they repeat, 'Pow, Pow,' and they fall in the ditch. All the day,'' he said, according to a transcript provided by Rambam.

''And then, 9 Oct. 1941, no more Jews ... no more Jews in Svencionilla,'' he added, referring to an area of Lithuania where Canadian government documents allege he was deputy police chief and then police chief from 1941 to 1944.

He did not admit to pulling the trigger but he supervised the Lithuanian police and their auxiliaries who rounded up the Jews and confined them, Canadian government submissions to the now-aborted deportation hearing said. The documents said a special Lithuanian unit acting on instructions from Nazi Germany actually executed them.

''I take great comfort that Kenstavicius is before the only judge that really matters,'' Rambam said.

Rambam turned over concrete information on Kenstavicius and another suspect to the RCMP. He said he was waiting to see if they would start proceedings on the other suspect before deciding whether to hand over further documentation.