An overwhelming majority of Canadian Alliance members have voted to merge their party with the Progressive Conservatives, leader Stephen Harper said Friday.

Calling it a "historic day," Harper announced the results of a mail-in vote at a news conference in Ottawa. All party members were eligible to vote.

Harper said 95.9 per cent voted to ratify the merger agreement, while 4.1 per cent voted against it. Of the 90,307 ballots mailed out, 53,315 were returned.

The proposed new conservative party will "challenge the Martin-Chrtien government" and end the "waste, corruption and mismanagement," said Harper.

Tories will vote on the issue Saturday after four days of delegate selection. They need support from two-thirds of the delegates to approve the merger.

The merger could be scuttled if a judge rules it contravenes the PC party's constitution. Former Tory leadership candidate David Orchard launched the lawsuit aimed at stopping the merger.

Orchard and 22 other Tories say MacKay broke his promise not to merge with the Alliance. They argue that under the PC party convention, the unanimous consent of all members is needed to unite with another party.

On Oct. 16, MacKay and Harper signed an agreement-in-principle to create a new Conservative Party of Canada.

Neither Harper nor MacKay have announced their official intention to run for the leadership of the new party.