Opposition members of the House of Commons committee on natural resources already have their backs up about who's appearing at hearings this week.

They want to know why Health Minister Tony Clement is going to get to testify tomorrow, Tuesday, January 29, when they didn't invite him.

The commmittee will be hearing from Linda Keen, the former head of the Canadian Nuclear Safety Commision, who was fired the night before she was to appear before a special hearing of the committee two weeks ago.

On Tuesday Keen will answer questions in public for the first time about her role in the isotope crisis last November and December.

The government accused Keen of being too hardline in her commision's insistence that safety upgrades be carried out before Atomic Energy's Chalk River reactor be allowed to restart.

They'll also hear from Auditor General Sheila Fraser who compiled a blunt and critical report on the serious issues facing Atomic Energy of Canada (AECL).

But now Health Minister Tony Clement is scheduled to testify right after Linda Keen.

Opposition party members have written letters objecting to his appearance.

They say it's a ploy by the government to get in the last word in the ongoing dispute with Linda Keen over who was to blame for the isotope shortage crisis.

They want Clement to show up but at some point later on. And they're prepared to pass a motion to say to the minister " go away and come back another day."

That would be "childish" says Conservative committee chair Leon Benoit, "the Minister will be there."

Benoit says he scheduled in Tony Clement after Clement asked to appear last week. He is taking a spot left open by the former head of AECL Michael Burns who declined an invitation to appear.

"He (Clement ) asked if he could come, I had an opening," says Benoit.

But the opposition parties say they won't let the government seize control over the agenda of the committee and they want to get to the bottom of the isotope issue.

Which means the committee could spend more time wrangling over procedural issues than hearing from its witnesses.