"We are heading towards a substantial deepening of the strategic partnership between Greece and France," Mitsotakis told state TV ERT during a visit to the French capital.

"There will be announcements tomorrow morning at the Elysee Palace" with French President Emmanuel Macron, he said.

The new deal may include the sale of Belharra frigates and possibly Gowind corvettes according to Greek reports earlier in the day, which would help a French defence industry smarting from the humiliating loss of a multi-billion-dollar submarine order from Australia.

Mitsotakis this month announced a surprise purchase of six French-made Rafale warplanes, in addition to a 2.5-billion-euro ($2.9-billion) deal for 12 used and six new Rafales signed in January.

Greece's burgeoning arms programme is designed to counter Turkish challenges in the eastern Mediterranean, against which France is among the few EU states to have offered public support in past months.

In turn, Mitsotakis has backed Macron's call for a European army.

"The demand for European strategic autonomy is absolutely imperative," he told ERT.

"Europe has the obligation to be able to act autonomously, if it so wishes," the PM said, adding that Greece and France would be "in the front line" of such an initiative.