The defence ministry confirmed to AFP on Saturday that men from the age of 17 "are required to obtain prior approval" from the German armed forces for foreign stays lasting longer than three months.

Approval will be granted as long as "no specific service as a soldier is expected during the period in question," a ministry spokesman told AFP.

"The background and guiding principle of this regulation is to ensure a reliable and informative military service record in case of need," the spokesman added.

The ministry is drafting exemptions to the exit permit requirement and a system for approving requests, aiming to "avoid unnecessary bureaucracy," the spokesman said.

A Frankfurter Rundschau newspaper report on the regulation on Friday prompted widespread social media discussion, with many people questioning whether it was real and why there was no public debate when military service reforms were proposed last year.

The new service law, aiming to attract more young Germans to volunteer for military training, went into effect in January.

Military service remains voluntary under the law. Germany suspended conscription in 2011.

But all 18-year-old men are now required to fill out a questionaire about their interest in military service and submit to medical checks if requested.

Germany has agreed to substantially increase the size of its full time and reserve army force as part of NATO defence plans.

European NATO allies have dramatically increased defence spending since Russia's 2022 full-scale invasion of Ukraine.