Lebanon will fund a UN-backed court that has charged Hezbollah operatives with the 2005 murder of ex-premier Rafiq Hariri, Prime Minister Najib Mikati announced.

"Lebanon's interest lies in financing the Special Tribunal for Lebanon, and the government will act in Lebanon's best interests," Mikati told the pan-Arab daily Al Hayat.

"When the time comes for the government to make a decision on funding the court, my decision will serve the interests of Lebanon."

According to the tribunal's 2007 founding text, Lebanon is responsible for 49 per cent of the court's finances. Beirut, however, has not yet paid its share for the year 2011 and in 2010 transferred the funds without approval of government.

Mikati's announcement broke ranks with his Hizbullah backers who have declared they will not cooperate with the tribunal and denounced it as "illegitimate."

In a recent interview with AFP, Agriculture Minister Hussain Haj Hassan, who represents Hizbullah in the Mikati government, said the movement would announce its position on funding the court "in due time".

The Netherlands-based tribunal, the only international court with jurisdiction to try an act of terror, has charged four Hizbullah operatives with the February 14, 2005 bombing that killed Hariri and 21 others in Beirut.

Hizbullah leader Hassan Nasrallah has slammed the tribunal as a US-Israeli conspiracy against the Shiite group and said the four indictees will never be found.

The Iranian-backed Hizbullah and its allies hold the majority of seats in the cabinet of Mikati, who rose to premiership in January after Hizbullah forced the collapse of Sa’ad Hariri's national unity government in a feud over the tribunal.

Lebanon's pro-Western opposition, led by Sa’ad Hariri, son of the slain Rafiq, has voiced fears that the terror group will isolate Lebanon from the international community and that its arms and militias – which dwarf the national military – undercut the sovereignty of the duly elected government in Beirut.

Hariri has been abroad for over five months due to fears Hizbullah, which recently said it was 'losing patience' with criticism from the opposition, may try to assassinate him as well.