OTTAWA — The Conservative party has revoked the membership of a former candidate after he sued the organization for allegedly reneging on a deal worth more than $50,000.

Party president Don Plett confirmed Friday that the Conservative national council voted to kick Alan Riddell out of the party.

Plett said he could not provide details because the decision was in arbitration, but another party official complained last May that Riddell was an "embarrassment'' to the party.

The decision comes as the party is under fire by some longtime members for disqualifying potential electoral candidates with little or no explanation.

Riddell is appealing to Prime Minister Stephen Harper to intervene and has brought his case before a party arbitration panel.

"The implication of this week's vote is that no loyal CPC (Conservative Party of Canada) member, such as I, is to be permitted to remain in the CPC if he-she turns to Canada's courts to implement an agreement ... even when all other attempts at redress have failed,'' he wrote Friday.

Riddell's dispute goes back to last winter's election.

He wanted another shot at running in the Ottawa South riding, after an unsuccessful bid in 2004. Initially, the party disqualified him as a candidate.

Riddell went to an arbitration panel and was eventually cleared to run. But soon after, he was persuaded to step aside for sponsorship whistleblower Allan Cutler. Cutler did not win the riding.

Riddell and the party entered into a financial agreement that would pay him up to $50,000 to compensate for expenditures to be the official candidate before Cutler arrived on the scene. In addition, Riddell would be repaid legal expenses.

When Riddell had trouble getting the money back from the party, he went public with the dispute. The party has since claimed they owe him nothing because he breached a confidentiality agreement.

Both sides now are embroiled in a breach-of-contract dispute in the courts. Harper's chief of staff Ian Brodie was forced to testify, since he was executive director of the party when the campaign to block Riddell's candidacy in Ottawa South began.

The campaign to remove him from the party began back in May. National council member Sam Magnus made the formal request, saying Riddell's lawsuit was "an embarrassment to the party, including a virtual harassment'' of party brass.>

Riddell's riding association wrote to officials, urging them not to eject the man and underlining his good standing with the Conservatives.

Over the last two weeks, Conservative officials have rejected applications from at least three party members to run for the nominations in their ridings.

The would-be candidates complain that the reasons they were blocked were not revealed, and they were asked to sign confidentiality agreements that barred them from discussing their situations later.