While he might be retired, the "Blue Homeland" vision that Rear Admiral Cem Gurdeniz helped craft over a decade ago is being turned into reality by Turkish President Recep Tayyip Erdogan today.

A 62-year-old Francophone and Francophile, Gurdeniz received AFP at a gorgeous wooden summer house on one of Istanbul's Prince's Islands in the Marmara Sea.

As warships from France, Greece and Turkey converged on a disputed patch of the eastern Mediterranean Sea, Gurdeniz looked at ease while criticising French President Emmanuel Macron.

"I'm fed up with Macron's everyday verbal threats," Gurdeniz said in English.

"For many Turks now, France is acting like an 'enfant terrible'. Can you imagine, they are threatening Turkey?" he asked.

"If France continues such provocative actions... that would not serve regional peace and stability -- that would add fuel to the fire and France should avoid that."

The discovery of major natural gas deposits in waters surrounding Cyprus and the Greek island of Crete have triggered a scramble for energy riches and revived old regional rivalries.

The biggest tensions are between historically uneasy NATO allies Turkey and Greece, which almost went to war over some uninhabited islets in the Aegean Sea in 1996.

These have been growing progressively more serious as Erdogan lays claim to waters designed to turn Turkey into the maritime powerhouse Gurdeniz envisioned from the start.

EU foreign ministers convened an emergency video conference last week after Greek and Turkish warships collided in hotly disputed circumstances.

"If Greece pulls the trigger, it will be the end of NATO," Gurdeniz said, implying that Turkey would then withdraw from the Cold War-era military alliance.

"European countries should put pressure on Greece so that it abandons" some of its maritime claims, he said.

- 'Cold blood' -

Erdogan has tempered his heated rhetoric with calls for talks, which have been spearheaded with sporadic success by German Chancellor Angela Merkel.

Gurdeniz agreed, saying: "We should think with cold blood, soberly, prudently."

But he saw no need for outside mediation, suggesting that hostilities will only end when Greeks and Turks sit down and frankly talk their problems out.

Gurdeniz overwhelmingly approves of Edrogan's tough line, but also regrets Turkey's growing diplomatic isolation in the increasingly volatile region.

He called Turkey's decision to rupture its relations with Egypt following the army's ouster of Islamist president Mohamed Morsi in 2013 "a mistake".

"Turkey could have won over Egypt. Also, starting with Egypt, we could have made some gains with Israel too," Gurdeniz said.

But his eyes lit up and his easy smile broadened when talking about the "growing interest of young people" in Turkey's maritime claims.

"I do a lot of interviews with YouTubers," said the retired admiral, pointing out that the annual enrolment of new cadets in navy schools is steadily rising.

He also pointed out that the Mediterranean accounted for just "one percent" of the world's oceans and seas.

"I always stress that Turkey should go beyond this one percent: the Red Sea, the Arabian Sea and the Atlantic," Gurdeniz said.

"Turkey should have a presence down there. This is the reflection of a growing power."