OTTAWA, Dec 4 (Reuters) - Canada has doubled the number of doses of Moderna Inc's COVID-19 vaccine it has on firm order, Procurement Minister Anita Anand said on Friday, while the country's top doctor warned that daily new cases could top 10,000 by January.

"Canada is exercising options for an additional 20 million doses of the Moderna vaccine candidate. This will bring Canada's total allotment of this vaccine to 40 million doses to be delivered in 2021," Anand said at a health briefing.

A regulatory review of the Moderna vaccine is ongoing. Canadian health authorities are expected to approve Pfizer Inc's competing vaccine candidate within the next week. The country has signed supply deals with seven manufacturers.

Canada reported 6,495 new cases of COVID-19 on Thursday, as infections surge across the country. Ontario, one of the worst-hit provinces, tightened restrictions in three areas on Friday, but did not expand lockdowns.

"If we stay on the same trajectory, we could reach 10,000 cases daily by January," Canada's chief public health officer, Theresa Tam, said, edging back earlier estimates that Canada would hit that landmark by mid-December.

Officials warned that Canadians will need to remain vigilant to slow the spread of the virus, even as vaccines begin to be rolled out. Canada is readying a plan to distribute the first six million doses of the Pfizer and Moderna vaccines in early 2021.

Anand said she is hopeful Canada will start getting vaccine shipments as soon as January and downplayed comments by Alberta Premier Jason Kenney, who earlier this week said his province had been assured shipments would start arriving by Jan. 4.

"We are working with a timeframe ... of Q1 2021," she said. "We are very hopeful it will be within the January timeframe," she added.

Anand also said FedEx Corp and Innomar Strategies, a Canada-based division of AmerisourceBergen, had been contracted by the federal government to provide logistical support on vaccine delivery.

(Reporting by Julie Gordon in Ottawa Editing by Leslie Adler and Grant McCool)