Haavisto said that proceeding with the joint application remained the first option. He nevertheless added that other routes would be considered if Sweden's NATO application became stuck in the long run.
Swedish Foreign Minister Tobias Billstrom reacted to his Finnish counterpart's latest statements, saying Sweden was in contact with its Nordic neighbor "to find out what is really meant."
Also on Tuesday, Turkey announced the unilateral postponement of NATO accession talks with Sweden and Finland scheduled for February.
In response, Swedish Prime Minister Ulf Kristersson urged collective calm and a return to dialogue, saying, "No national security question is more important than that we, with Finland, quickly become members of NATO."
Erdogan was reacting to an anti-Islam protest in Stockholm on Saturday, during which the Quran was burned outside the Turkish embassy. A separate Kurdish protest was also held in the Swedish capital on the weekend.
"It is clear that those who allowed such vileness to take place in front of our embassy can no longer expect any charity from us regarding their NATO membership application,'' Erdogan said.
The Swedish government tried to distance itself from the demonstrations, openly condemning the Quran burning incident for any offence it may have caused Muslims. However, the government maintained its wide freedom of speech principles.
Speaking on Tuesday, Finland's Haavisto said that the protest toyed with both Finland's and Sweden's security, by stalling the NATO bid.
Joint NATO bid
Both Finland and Sweden have for decades maintained a neutral military stance within Europe and beyond. However, Russia's invasion of Ukraine last year prompted the Nordic neighbors to change course, seeking for the first time a NATO membership.
In order to join the alliance, the duo must secure the unanimous approval of all members. Turkey has been vocal about its reservations, citing the countries' support to and hosting of what it describes as "terrorists," in reference mostly to exiled Kurds.