Turkey said on Wednesday Sweden's new government was more determined to address Ankara's security concerns in return for NATO membership but called for "concrete steps".

Foreign Minister Mevlut Cavusoglu met with his Swedish and Finnish counterparts on the sidelines of a NATO gathering in Bucharest on Tuesday.

Ankara has accused the two Nordic nations -- especially Stockholm -- of providing a safe haven for outlawed Kurdish groups it deems "terrorists" and held back on ratifying their NATO bids despite an agreement in Madrid in June.

"The statements (coming out of Sweden) are good, the determination is good but we need to see concrete steps," Cavusoglu told reporters in Bucharest.

"We told them we haven't seen concrete steps on these issues" including the extradition of criminals and freezing of terror assets.

Sweden's Foreign Minister Tobias Billstrom spoke optimistically about Tuesday's meeting.

"And I have to say that I felt after this meeting that yes, there is progress in line," he said.

"We are moving forward with the implementation of a trilateral memorandum which was signed in Madrid."

Finland and Sweden dropped decades of military non-alignment and scrambled to become NATO members in May, after Russia invaded Ukraine.

The decision requires a consensus within the US-led defence alliance, but only Turkey and Hungary are yet to give consent to their membership.