Boris Johnson is scheduled to meet leaders of both countries during a whirlwind 24 hours.
With Queen’s Speech debates in the Commons meaning there is no Prime Minister’s Questions on Wednesday, Mr Johnson will take the opportunity to refocus the spotlight on Europe’s response to the war in the east of the continent.
The visit comes as Sweden and Finland consider whether to apply for Nato membership in the wake of Russia’s invasion of Ukraine.
No 10 said it was “disinformation” to suggest Mr Johnson was seeking to put pressure on them to join the western military alliance.
“It is about not just Ukraine but the security of Europe more broadly,” the Prime Minister’s official spokesman said.
“We understand the positions of Sweden and Finland and that is why the Prime Minister is going to discuss these broader security issues.”
Support for joining Nato has risen sharply in both countries since Russia invaded Ukraine, despite their previous tradition of neutrality.
In her Mansion House speech last month, Foreign Secretary Liz Truss said that if they did apply for membership, they should be admitted “as soon as possible”.
Mr Johnson held talks with Swedish prime minister Magdalena Andersson and the Finnish president Sauli Niinisto in March as part of a meeting of the Joint Expeditionary Force nations, which includes Denmark, Estonia, Iceland, Latvia, Lithuania, the Netherlands and Norway.
After the meeting Downing Street said the two leaders agreed that “Putin’s invasion had dramatically changed the landscape of European security”.
Finland shares a lengthy land border with Russia and is only about 250 miles from St Petersburg.
