In another response to Russia's invasion of Ukraine meanwhile, Finland's state-run alcohol distributor took vodka off the shelves.

According to the survey, commissioned by public broadcaster Yle, 53 percent of Finns backed their country joining the military alliance, 28 percent opposed it, and 19 percent were unsure.

"A completely historic and exceptional result," Charly Salonius-Pasternak, Senior Research Fellow at Finnish Institute of International Affairs, told AFP. "The change is dramatic."

The poll surveyed 1,382 respondents between the ages of 18 and 80 between February 23 and 25, said Yle.

In contrast, a January poll published by Helsingin Sanomat newspaper had only 28 percent in favour and 42 percent against NATO membership.

"The only significant thing that has changed is that Russia has attacked a neighbouring country that is not a member of NATO," Salonius-Pasternak said.

Although the results of the latest poll could be an effect of the initial shock at the Russian invasion, the researcher said he believed support would likely remain at a higher level.

- Petition for parliamentary debate -

When Yle last commissioned a similar poll in 2017, support for NATO membership was at 34 percent.

But Finland's president Sauli Niinisto said early last week the debate around joining the alliance could be reignited by Russia's actions in Ukraine.

And last week, a petition to have Finland's parliament debate a referendum on NATO membership gathered the necessary 50,000 signatories to force a parliamentary debate. It is still to be formally submitted to parliament for review.

Finland shares a 1,340-kilometre-long (830-mile-long) border with Russia. While neither it nor neighbouring Sweden are NATO members, both countries are partners of the Western military alliance.

Faced with Moscow's demands that NATO not expand eastwards, Helsinki and Stockholm have rejected any Russian interference in their security policy.

Both countries have received assurances from NATO that the door remains open to them, though the Social Democrats in power in both countries have no plans to join.

In another response to Russia's invasion of Ukraine meanwhile Alko, Finland's state-run alcohol distributor, took vodka and other Russian products off the shelves Monday.

"The situation in Ukraine is shocking and we have taken it seriously," said spokesman Anu Koskinen, announcing the suspension of both in-store and online sales.

The measure will affect around 30 Russian products -- most of them vodka -- from its total stock of 11,000 items.