Beirut: The speaker of the Lebanese parliament has warned Prime Minister Najib Mikati's government will collapse if it fails to draft a programme by July 13, amid a deepening rift over a UN-backed tribunal.

"According to the Lebanese constitution, when you form a cabinet you have 30 days to present a policy statement to parliament," an official in speaker Nabih Berri's office told AFP on condition of anonymity.

"If that does not take place, the cabinet automatically collapses."

A drafting committee has held six meetings to try to finalise the programme but has repeatedly ducked the divisive issue of cooperation with the Special Tribunal for Lebanon, which has been investigating the 2005 assassination of ex-premier Rafiq Hariri.

The court is expected to issue indictments against members of Iranian- and Syrian-backed Hezbollah over the killing. The militant group, which leads the majority bloc in parliament, wants the new government to cut all ties with it.

Lebanon's previous government collapsed in a feud over the court.

Observers say that Mikati, a billionaire businessman, has baulked at Hezbollah's demand.

Berri, a Hezbollah ally, said that under the constitution, parliament would have to begin consultations on naming a new prime minister if the Mikati government failed to publish its programme by the July 13 deadline.

Mikati on Wednesday reiterated his belief that his cabinet programme should "take into account the interests of Lebanon" without neglecting international resolutions, adding that he would take "the necessary action" should his government fail to meet the deadline.

"I will not get involved in arguments over the constitution," Mikati told reporters in response to a question.

"What is certain is that if we do not finalise the ministerial statement by the constitutional deadline, I will take measures that reflect my respect for the constitution and the nation."