One of the defendants, Bruce Balfour, 52, is in custody and attended the hearing before a military tribunal. A warrant for the arrest of the second man, Grant Livingstone, 81, has been issued and he will be tried in his absentia.

No Canadian diplomat attended the public hearing.

Both Protestant pastors are alleged to have spied for Israel, where they live, "under cover of humanitarian activities" during several visits to Lebanon, according to the charges against them.

Balfour, from Alberta, lived in Lebanon for four years from 1982, when the country was invaded by Israel. He returned twice briefly in 2002 with the alleged intention of overseeing a reforestation project.

He was arrested on his most recent return to Beirut on July 10 of this year.

It is alleged that he made contact with the agriculture ministry and travelled to the hills in southern Lebanon with the aim of gathering information about military positions and the Shiite radical group Hezbollah, operational in the region.

Livingstone wrote a book about his time in Israel and is suspected of having assisted Balfour in his activities for the Jewish state.

If found guilty, they face three to 15 years hard labour.

The Canadian government said in Ottawa on Wednesday "there is no reason to overdramatise" Balfour's case, while it awaited to hear the exact nature of the charges he faces. No mention was made of Livingstone in government spokesman Reynald Doiron's statement.