"We have been working like crazy," Theresa Oswald, the former jobs and the economy minister who led a caucus revolt against Selinger, said as she dropped off a small stack of new memberships at party headquarters.
"We set ourselves a very ambitious target a couple of weeks ago of about 700 (new) members across the province. I believe we're on target to achieve that."
Selinger was not available for comment, but an official with his campaign said every effort was being made to ensure supporters had bought or renewed party memberships.
The third candidate in the race, Steve Ashton, wasn't available either. His spokesman said Ashton was focused on getting in membership applications.
Membership in the party had climbed to 9,335 by Monday. That was up from roughly 7,000 at the start of December, but below the more than 12,000 members during the NDP's last leadership race in 2009.
The governing New Democrats plummeted in opinion polls in 2013 after raising the provincial sales tax to eight per cent from seven. Last October, Oswald and four other senior ministers went public with suggestions that Selinger resign for the good of the party. They soon after resigned their portfolios to sit on the backbenches.
Oswald — who previously served as health minister and has enjoyed a high profile within the party — has been promoting herself as the best candidate to revive the party's fortunes and take on Progressive Conservative Leader Brian Pallister in the next election, slated for April 2016.
"I think what you will see is a difference in style, a difference in approach, and a difference ... in our ability to really compete in 2016 against Mr. Pallister. I think that's the difference that I offer that perhaps Mr. Ashton and Mr. Selinger don't," she said.
Ashton, a former transportation minister who did not take part in the revolt against Selinger, is promoting himself as someone who can unite the fractured party. He ran against Selinger for the leadership in 2009 and finished a distant second with 33 per cent of the vote.
Selinger has been keeping a low profile. He has said he wants to focus his energy on governing the province and has rejected calls from some quarters to step down from the premier's chair during the race.
The three candidates have yet to find out which labour groups will support them. Under the NDP constitution, unions and other groups are granted delegates to the leadership convention based on their membership levels.
Alex Forrest, head of the 1,800-member United Fire Fighters of Winnipeg union, said his group would wait until close to the convention to back a candidate.
The union backed Ashton last time, but Forrest said he was eyeing all candidates to see which one "is going to be able to unify the party ... and going to be able to heal the rifts that have occurred."
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