A record number of New Democrats can vote for the party's new leader next month, after candidates ramped up efforts to sell memberships.

The number of card-carrying NDP members across Canada has jumped to 128, 351 from 83,824 in October -- an increase of more than 50 per cent -- the party revealed Tuesday.

The biggest gains were seen in Ontario and Quebec, with about 14,500 and 10,500 new NDP members respectively.

To accommodate all registered delegates, the NDP booked the sprawling Metro Toronto Convention Centre for its March 24 leadership convention. Those who wanted to join the NDP in time to vote had until Saturday to register.

"Canadians are really engaged and involved in our leadership race -- as these historic numbers show," NDP National Director Chantal Vallerand said in a news release, adding that people are turning to the party "in record amounts in order to defeat" Prime Minister Stephen Harper.

The NDP is hoping that its next leader can carry on the party's historic gains in the last federal election, which elevated it to Official Opposition status for the first time.

In the running are: Brian Topp, Nathan Cullen, Paul Dewar, Niki Ashton, Peggy Nash, Thomas Mulcair and Martin Singh.

They've all worked hard to recruit new NDP members to vote for them. Party membership cost up to $25, depending on the province.

The NDP saw its biggest election surge in Quebec, which accounts for more than half of the NDP's 101 seats in the House of Commons. There are now 12,266 NDP members in the province, compared to just 1,700 in October.

Even though Quebec still has less than 10 per cent of the NDP's total membership, the province will still be closely watched by the rest of the country, given the party's "historic breakthrough" in the province, Alice Funke of Punditsguide.ca told CTV's Power Play.

New Democrats will have to work hard to keep Quebeckers – and the rest of Canada -- engaged, she said.

Another province rising in strategic importance for the NDP is British Columbia, which has the highest number of members in the country -- 38,735, an increase of more than 8,000.

As a result, leadership candidates are spending more time in B.C., CTV's Richard Madan reported.

He said the membership increase has "boosted some optimism across the board" for the NDP, which is struggling to fill the void left by Layton.

Because NDP memberships are also being sold online this year, Madan said it's difficult to tell who among the leadership candidates has had the most success in attracting new members. That will be revealed at the leadership convention.

This time around, registered delegates can also vote online before the convention, which will move the race away from "old style" campaigning, Madan said.

Funke said it's hard to peg frontrunners at this point in the race. Candidates are expected to campaign heavily leading up to the convention, especially in B.C. and Ontario, she said.

"I think it's going to be very, very competitive."

Below are the latest membership numbers provided by the NDP, compared to October figures (in brackets):

• Alberta - 10,249 (9033)
• British Columbia – 38,735 (30,000)
• Manitoba – 12,056 (10,307)
• New Brunswick - 955 (Not previously reported)
• Newfoundland – 1,030 (200)
• Nova Scotia – 3,844 (1,300)
• Northwest Territories/Nunavut/Yukon - 924 (Not previously reported)
• Ontario - 36,760 (22,225)
• Prince Edward Island - 268 (135)
• Quebec - 12,266 (1,695)
• Saskatchewan - 11,264 (8,929)
• TOTAL - 128,351 (83,824)