Switzerland is to join the European air defence system, Sky Shield.
The agreement does raise questions about Swiss neutrality as it will be aligning with most NATO countries that are members.
This country will also become a member at the same time as fellow neutral state Austria.
The Federal Defence Department says there are no plans to combine the defence systems – but it will allow joint training and equipment procurement.
The government says it will outline its position on why joining the pact is not a violation of neutrality in an upcoming document.
The Defence Minister, Viola Amherd, has already signalled her desire to work more closely with NATO when she met the Secretary General, Jens Stoltenberg, earlier this year.