Tspiras on Sunday called for a confidence vote in parliament over the resignation of defence minister Panos Kammenos, leader of a party that left the coalition in protest over a name change deal with neighbouring Macedonia.

His resignation raises the possibility of snap elections and the parliament speaker said debate over the confidence motion may start on Tuesday with a vote as early as Wednesday night.

Armed forces chief of staff Admiral Evangelos Apostolakis on Monday said he had accepted the defence minister post.

"The current situation requires compromise and unity," Apostolakis told journalists before a meeting with Tsipras.

Tsipras' leftist Syriza party has 145 deputies in the 300-member Greek Parliament but could win the confidence vote with just 120 votes if enough lawmakers abstain.

Kammenos is head of the nationalist Independent Greeks party (ANEL) which has seven MPs and is fervently opposed to a deal with Macedonia to end a dispute over the country's name.

Macedonian lawmakers voted on Friday to rename their country the Republic of North Macedonia but the agreement will only come into effect with backing from the Greek parliament.

The proposal faces resistance in Greece, which has a northern province of the same name, over implied claims to Greek land. For many Greeks, Macedonia is the name of their history-rich northern province.