"This is a deadline that automatically spells the end of the government, and not a timeframe that is meant to merely encourage them to draft a programme," Nabih Berri, Lebanon's house Speaker said, in comments published Wednesday by Beirut daily As-Safir.
A drafting committee has held six meetings to try to finalise the programme but it has repeatedly ducked the divisive issue of cooperation with the Special Tribunal for Lebanon, whose prosecutors have been investigating the 2005 assassination of ex-premier Rafiq Hariri.
The court is expected to issue indictments against members of Hizbollah over the killing and the Shiite militant group, which leads the majority bloc in parliament, wants the new government to cut all ties with it.
But observers say that Mikati, a Sunni billionaire buisnessman, has baulked at Hizbollah's demand.
Berri -- a Hizbollah 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.