OTTAWA - A long-delayed probe of the 1985 Air India bombing has hit another snag, as counsel for the commission of inquiry and the federal government haggle over how much of the evidence can be made public.

The inquiry, headed by former Supreme Court justice John Major, has been in recess for over three months. It is scheduled to resume with a brief public hearing Monday.

But sources say the proceedings will be limited to formal statements by the parties involved, including Mark Freiman, the chief counsel for Major, and lawyers for the government and the families of the bomb victims.

The plan had been to go on after that to hear from present and former members of the RCMP and the Canadian Security Intelligence Service. But their testimony will now be postponed for another two weeks.

It's hoped that, in the meantime, there can be a meeting of minds on two points -- the vetting of written documents to safeguard national security, and the extent of oral testimony that will be heard in open session.

 Government lawyers warned last fall they would insist that some witnesses be heard behind closed doors, and some documentation remain secret because of continuing security concerns -- even though many of the matters under scrutiny are two decades old.

Major, for his part, has said repeatedly he wants most of the proceedings to be accessible to the families who lost loved ones and to the media.

"Some of this is uncharted territory,'' a commission source said Sunday. "But we want to ensure that as much as possible can be heard in open hearings. We want to spend as little time in camera as possible.''

Agreement has been reached on thousands of pages of documents expected to be tabled Monday, with portions blacked out for security reasons.

But differences remain on other key papers, and on how far counsel can go in questioning witnesses about them during oral testimony. The aim now is to cut a deal on those points and avoid asking Federal Court to sort out the dispute -- a course that would delay the inquiry's work even longer.

Some 329 people, the vast majority of them Canadian citizens of Indian origin or descent, died when Air India Flight 182 was blown from the sky by a terrorist bomb in June 1985.

It's already known the attack was the work of Sikh separatists who used British Columbia as a base to mount their campaign for a homeland in the Punjab region of northern India.

Some of the key suspects were under surveillance by CSIS long before the plane went down. There had been warnings of a general nature that Indian government institutions, including the state airline, could be targeted by extremists.

But no one pieced together the parts of the puzzle in time to thwart the plot. The question of why not is one of the central issues under investigation. 

 The star witness on Monday -- now put off until March 5 at the earliest -- was supposed to be RCMP Const. Lynne Jarrett, or Lynne McAdams as she was known in 1985 when she worked for CSIS.

Less than three weeks before Flight 182 was bombed, she and a partner trailed Talwinder Singh Parmar, founder of the militant Babar Khalsa sect, and Inderjit Singh Reyat, a local auto mechanic, into the bush on Vancouver Island.

The spies didn't see exactly what happened there, but they heard a loud bang which they interpreted at the time as a rifle shot suggesting the two might be engaged in firearms training.

Although CSIS notified the RCMP of the incident, nobody conducted an immediate search of the area. It wasn't until after Flight 182 had gone down that the Mounties combed the woods and found evidence that what had transpired was an explosives test, not target practice.

It wasn't the last snafu in the case. It later turned out CSIS had erased key wiretap tapes of Parmar and others, a move that hampered RCMP  efforts to gather evidence for a criminal prosecution.

The Major inquiry has a mandate to delve into all of that, along with a wide range of other matters including airport security, terrorist financing, ways to provide better protection for witnesses, and the possibility of assigning future terrorist trials to three-judge panels rather than a single jurist.

But the judge has been travelling a more arduous road than he anticipated in the 11 months since Prime Minister Stephen Harper named him to his post in March 2006.

It took until June to hire staff, draw up preliminary plans and hold an opening hearing at which Major vowed to get to the bottom of what he called "the most insidious episode of cowardice and inhumanity in our history.''

There were three weeks of emotional testimony last fall by victims' families, who relived the horror of their loss. Major planned to follow immediately with the government side of the story, but hearings were abruptly suspended in November when it became apparent that counsel would need more time to prepare.

Reyat is the only person ever convicted, on a reduced charge of manslaughter, for his role in the bomb  plot. Parmar, the suspected ringleader, slipped out of Canada and was shot dead by Indian police in 1992. Two more men, Ripudaman Singh Malik and Ajaib Singh Bagri, were acquitted in Vancouver in 2005.