French President Emmanuel Macron has signed the membership protocols for Finland and Sweden's accession to join the Nato alliance, according to a press statement released by the Élysée Palace.

"This sovereign choice of Finland and Sweden, two European partners, will reinforce their security in the face of a real menace in their immediate neighbourhood and bring a significant contribution, with respect to the capacities of these two partners, to the collective posture and our European security," Macron said after signing the protocols.

The French Senate and the lower house of parliament, the National Assembly, had previously approved and ratified the membership applications by Finland and Sweden.

Some 23 out of 30 Nato member countries have so far ratified the membership applications submitted by the two Nordic nations in May.

The lower house of the Czech parliament is expected to give the green light to the membership bids at the end of August.

Six member states - Slovakia, Hungary, Spain, Portugal, Greece and Turkey - have not yet approved the applications.