A closed-door discussion over whether to end the study into Canada's F-35 purchase has led to a verbal battle between the committee's NDP chairman and the sole Liberal member over the rules.

On Tuesday, Liberal MP Gerry Byrne used his time in question period to ask NDP MP David Christopherson why his motion to call witnesses hadn't been heard.

It's unusual for an opposition MP to provide an answer during question period, but the rules allow for committee chairs to respond to direct queries.

"Despite my motions having been previously called and still up for debate, the chair has chosen not to allow them to proceed," Byrne said. "Why has the chair not allowed my motions to be dealt with and will he commit that before proceeding to other business he will allow my motions to be properly debated and properly voted on?"

The seemingly dry procedural issue has ignited a fiery back-and-forth while the committee debates ending its study into the controversial plan to buy F-35 fighter jets to replace the current fleet of CF-18s.

Christopherson said he ruled one of Byrne's motions out of order and would rule on the other at the next meeting of the public accounts committee.

'Dishonourable crybaby'

On Thursday, Christopherson emerged from that meeting and accused Byrne of making a personal attack in question period.

"Mr. Byrne has chosen that because he can't get the rulings he wants, that he is going to hold whatever tantrums are necessary to convince the world that he's right and the rest of the world is wrong," Christopherson said.

"And on this matter, in my opinion, Mr. Byrne has been a dishonourable crybaby and because he doesn't have enough talent to come up with procedures that will let him win, he starts to argue the rules are unfair."

Byrne is the sole Liberal member on the committee, on which Conservative MPs outnumber opposition MPs.

"If you attack me, I’m from Hamilton. You attack me, I’m going to attack back. And that was a dishonourable, unnecessary attack. And I just responded," Christopherson said.

The MPs said they haven't yet decided on whether to end the study into the fighter jet purchase. Conservative MP Andrew Saxton says they've heard enough and that it's time to write the report.