The former chairman of the B.C. New Democratic Party caucus says he quit because NDP MLAs weren't consulted before Leader Carole James ejected one of them.

Norm Macdonald said in a statement Monday he had no option but to resign last Friday, almost one week after James unilaterally dumped Cariboo North MLA Bob Simpson from caucus over comments Simpson made in an online column.

"The decision to remove a member from caucus should not be made unilaterally by the leader," wrote Macdonald, MLA for Columbia River-Revelstoke.

"The leader has a responsibility to first consult with caucus and that did not happen in this case."

Simpson was kicked out of caucus after he criticized James's speech to the province's municipal politicians last month as devoid of ideas.

After he was dumped, Simpson said James has yet to prove herself as a leader worthy of becoming premier of British Columbia and his constituency association has called for a full leadership contest at the party's convention in November 2011.

On Friday, James acknowledged that Macdonald quit caucus over concerns Simpson's punishment was too harsh.

But Macdonald said Monday that's inaccurate.

He said he couldn't remain as caucus because when James acted alone, she defied a core NDP value requiring fair treatment for everyone.

"I have fundamental differences with the leader on what the role of caucus should be. I believe that caucus members must be part of the decision-making process," he wrote.

"The decision to resign was not an easy decision to make, but it was my only option. I have to stand up for what I know is right."

Macdonald said his constituents expect him to live up to his principles even when it is uncomfortable and inconvenient to do so.

"While knocking on doors, voters told me that they want a representative who would work hard to make our democratic system work better," he wrote.

"My responsibility is to the people who elected me."

Macdonald will remain a member of the NDP caucus and James has appointed Burnaby-Deer Lake MLA Kathy Corrigan to take over as caucus chair.