Norway's Health Ministry said the doses would be returned if the country resumed use of the AstraZeneca jab.
Norway has lent all 216,000 of its AstraZeneca COVID-19 jabs to neighbouring Sweden and Iceland.
Norway's Health Ministry said the doses would be loaned only if the country continues to suspend the use of the AstraZeneca jab (Vaxzevria).
On March 11, Norway followed Denmark in deciding to pause the rollout of the jabs by the British-Swedish company after reports of extremely rare blood clots and continued to innoculate citizens with other jabs developed by Pfizer/BioNTech and Moderna.
"Sweden and Iceland want to borrow Norwegian doses of vaccines from AstraZeneca that are in stock at the National Institute of Public Health," the ministry said in a statement.
"Norway will lend doses to Sweden and Iceland as long as the vaccine is on pause in this country."
Sweden will receive 200,000 doses of Vaxzevria, while Iceland will be donated 16,000 from the stock, the ministry added.
The loaned vaccines have a shelf life that expires in June and July.
"I am glad that the vaccines we have in stock will be useful even if the AstraZeneca vaccine is put on pause in Norway," said Minister of Health, Bent Høie.
"Sweden has a demanding infection situation and has provided extensive support to Norway in the work with vaccine access."
But Høie reiterated that Sweden and Iceland would return the doses if Norway's own government regulator resumed use of the vaccine.
"If the use of the AstraZeneca vaccine is resumed, we will get back the doses we lend as soon as we request it," the minister said.
"Sweden and Iceland will then send back the doses from their first deliveries from AstraZeneca."
The European Medicines Agency (EMA) has said that the benefits of being immunised against COVID-19 outweigh the very rare risk of developing the blood clots possibly linked with the British-Swedish jab.
Non-EU member Norway also said that in the future their vaccines could be donated to other countries in the bloc "in collaboration" with Brussels.
Although the Norwegian Institute of Public Health has recommended removing the AstraZeneca vaccine from Norway's vaccination program, the government has decided to wait, saying it "believes that we do not have a good enough basis for drawing a final conclusion."
The country's health ministry reiterated that experts would examine the use of Vaxzevria and the Johnson & Johnson vaccine - which use the same adenovirus technology - before May 10.
On Tuesday, Denmark said it would also be lending 55,000 AstraZeneca doses to the neighbouring German state of Schleswig-Holstein.
The Danish government said they had "not yet decided" what to do with the other surplus vaccines, but were in dialogue with several countries.