TORONTO -- Ontario is considering whether to delay administering the second dose of the COVID-19 vaccine, ahead of a potential shortage of doses in Canada.

Health Minister Christine Elliott confirmed to CTV News Toronto on Friday that the province is looking at extending the full immunization window from three weeks up to 42 days, allowing the province to distribute initial doses to as many people as possible.

"The National Advisory Council on Immunization (NACI) has said up to 42 days between the doses is acceptable and is safe," Elliott said. "It would be within Ontario's power to extend the doses up to that time."

While the advisory council lists 19 to 28 days as the ideal interval between the first and second doses of the COVID-19 vaccine, it allows provinces to delay the final injection by up to 42 days for maximum effect.

"Some jurisdictions considering vaccine delivery logistics, current epidemiological status and projections, and healthcare system capacity may maximize the number of individuals benefiting from a first dose of vaccine by delaying the second dose," the council's recommendations on the COVID-19 vaccine states.

The consideration comes after the federal government announced a "temporary" delay of the Pfizer-BioNTech vaccine shipments due to expansions of the company's European manufacturing facility -- resulting in a 50 per cent cut in shipment in January.

Ontario was expecting to receive more than 160,000 doses of the Pfizer-BioNTech vaccine in the final two weeks of January, according to the federal government, a delivery schedule that's now in doubt.

Elliott says the province is awaiting further details on the "the exact allocations" and the "timing of those allocations" but said the province is once again reserving vials of the vaccine to ensure second doses are administered.

"We have some in reserve to make sure that we are going to be able to do the second doses in the appropriate period of time. So no one needs to worry about whether they will get their second dose or not.

So far, Ontario has administered 174,630 doses of the Pfizer-BioNTech and Moderna vaccines, with 17,094 people receiving both doses.