Turkish President Recep Tayyip Erdogan has called for territorial "improvements" in the Aegean Sea on the eve of a state visit to Greece, in comments that are likely to raise hackles in Athens.

"Airspace and territorial waters and the different measurements can be improved," Erdogan told Greece's Skai TV on Wednesday, ahead of what will be the first official visit by a Turkish president in 65 years.

"And I think there are certain problems that can be easily surmounted, and I think if we can surmount those challenges both of the countries will be relieved," said Erdogan, who last visited Greece in 2010, when he was prime minister.

Relations between Turkey and Greece have been fraught with territorial disputes in the Aegean, with the two NATO allies nearly going to war in 1996 over uninhabited islands.

Greece claims sovereign airspace extending 10 miles (16 kilometres) from its coastline and islands, but Turkey recognises only six miles, arguing that under international law Greece's airspace should match its limits for territorial waters.

As a result, there are often confrontations when Turkish warplanes enter airspace that Greece claims as its own, prompting Greek authorities to scramble jets in response.

To Athens's annoyance, Turkey also says there are a number of Greek islets and islands whose sovereignty remains unclear.

In the interview, Erdogan also repeated his view that the 1923 Treaty of Lausanne, one of the defining documents in Greek-Turkish relations, should be revised.

"I think during the course of time, all of the treaties need a revision, and Lausanne in the face of the recent developments needs to be spruced up, a revision if you will," Erdogan said.

"This revision is not only for Turkey, but also it's for Greece, it could be mutually beneficial."

Earlier this week, a Greek government spokesman said Athens was hoping for a "substantial improvement" in relations to emerge out of Erdogan's visit.

But he also emphasised that the treaty of Lausanne was "binding" and "in force".

In an interview with Turkey's Anadolu news agency, Prime Minister Alexis Tsipras said relations with Turkey had to be based on "mutual respect and international law, with full respect to the treaty of Lausanne."

But Erdogan said existing territorial waters were "quite problematic" for Turkish maritime liners plying the Aegean, "and this is not something that we can live with."

He did not give further detail.

He also repeated a request that eight officers who fled to Greece after allegedly participating in the attempted coup against him last year should be extradited.

"(Tsipras) said he was going to follow up the situation, and not later than a fortnight they shall be extradited to Turkey. That was what he said. But, unfortunately, right now, they are still in Greece," Erdogan said.

The Greek Supreme Court has blocked the extradition of the officers, and Erdogan lamented that taking the legal route "takes longer".

"Terrorists, when they are detained in Greece, they should be extradited to Turkey. If you leave it in the hands of the judiciary no outcome can ever be cultivated and you won't be able to cultivate any results," he said.

"Delayed justice is no justice."

Source:AFP