NATO Secretary General Jens Stoltenberg arrived in Harpsund in Sörmland just before 1 p.m.
On Sunday, he said Turkey had "legitimate concerns" about terrorism and other issues that needed to be taken seriously.
Turkey has accused Finland and Sweden of supporting Kurdish militants and says they will not support the two Nordic nations that join NATO until they change their policy.
Terrorist attacks in Turkey
At a joint press conference with Finnish President Sauli Niinistö on Sunday, Stoltenberg emphasized that "no other NATO ally has been hit by more terrorist attacks than Turkey" and pointed to its strategic geographical location with neighbors such as Iraq and Syria, the AP reported.
Stoltenberg will also take part in discussions with the Swedish government in addition to the discussions he has with the Prime Minister on Sweden's and Finland's applications to NATO.
Finnish President Niinistö stated at the press conference on Sunday that Finland will not join NATO if Sweden's problems with Turkey cause Swedish membership to be postponed, Norwegian NRK reported.