Originally signed in September 2014, the HNSA with NATO would allow the alliance to transport helicopters, aircraft and ships across Swedish territory, but only upon Sweden’s invitation, reported.

As the agreement involves changes to Swedish law in order to give NATO personnel privileges and immunities with regards to areas like tax and custom rules, it required parliamentary ratification. After the stamp of approval it is expected to come into force on July 1, 2016. 

Public opinion in traditionally non-aligned Sweden has shifted toward NATO in recent years.

A Sifo poll released in September 2015 showed a marked change, with more Swedes in favour of joining the military alliance than against. 

Of the 1,000 respondents, a total of 41% told the poll they were in favour of seeking membership in the military defence alliance, 39% said they were against it and 20% were uncertain.