Conservative Prime Minister Kyriakos Mitsotakis is due to unveil to parliament on April 2 the details of the sweeping 11-year plan to reform the armed forces.

"In all, the country's new armement programme provides for an average expenditure of 2.16 billion euros per year. That totals nearly 26 billion euros between now and 2036," the source told AFP.

The planned reforms were outlined in November by Defence Minister Nikos Dendias, who said Greece needed to modernise so it could cope with the defence challenges of the 21st century.

Central to the programme is a multi-pronged air defence system dubbed Achilles Shield, which integrates anti-missile, anti-drone and anti-aircraft technology.

Greek media reports have said the government is in talks with Israel to acquire multiple rocket launch systems for this purpose.

The programme also includes the purchase of 20 F-35 fighter jets.

An agreement has already been signed for the aircraft, which are due to be delivered in 2030.

Greece is one of only four NATO countries to devote more than 3.0 percent of its gross domestic product to defence spending, a strategy triggered largely by long-standing tensions with neighbouring Turkey.

Within the military alliance, only Poland, Estonia and Latvia spend more on defence than Greece.

France, Germany and Poland also announced recently they want to strengthen their armed forces and European Commission president Ursula von der Leyen has said the 27-member European Union should significantly increase spending on weaponry.

Athens has earmarked 6.13 billion euros for defence this year, largely to pay for deliveries of equipment. This is nearly double last year's budget of 3.6 billion.