ATHENS, Jan. 21 (Xinhua) -- Greek MPs will vote on the Macedonia name deal on Thursday, Parliament Speaker Nikos Voutsis announced on Monday, as the government voiced optimism over the result.

Support for the agreement will increase in both society and the assembly through the parliamentary debate starting Tuesday, as the various points that give rise to tension are explained in detail, government spokesman Dimitris Tzanakopoulos told local radio 24/7.

Following a mass rally against the agreement staged on Sunday in Athens, the Greek official said that the government was aware that a part of the Greek society opposed the deal.

According to several opinion polls, 65 percent to 80 percent of Greeks oppose the agreement clinched last summer between the governments of Greece and Former Yugoslav Republic of Macedonia (FYROM) to end a 28-year old dispute over the use of the term "Macedonia".

Under the deal, FYROM will be renamed Republic of North Macedonia and the road to its accession to EU and NATO will open.

The agreement was ratified by the parliament of Skopje a few weeks ago, despite similar objections.

Skeptics in Greece have not been convinced that the deal leaves no room at all for future territorial claims by the neighboring state.

The government will act in accordance with what it considers to be its patriotic duty and in the best interests of Greece, Tzanakopoulos said on Monday.

He appeared confident that the deal would be ratified by over 151 votes in the 300-member strong plenary.

The ruling Radical Left SYRIZA party holds 145 seats after the departure of the junior partner in the government coalition earlier this month due to objections to the deal.

Greek Prime Minister Alexis Tsipras counts on the support of opposition deputies, in particular independents.

Meanwhile, diverging views over the agreement have caused rifts in small opposition parties. Two MPs announced on Monday that they quit the parliamentary group of the centrist Potami (River) party, because they did not agree with the leadership's intention to back the agreement.

In addition, MP and Democratic Left (DIMAR) leader Thanassis Theocharopoulos was expelled from the Movement for Change (KINAL) centre-left coalition's parliamentary group, after announcing that he will also vote in favor of the agreement.

Greek police has identified lately at least 30 people who are suspects of sending various threatening messages to MPs supporting the agreement, Greek national news agency AMNA has reported.