The opposition refused to delay discussions on the electoral law, suggesting that talks continue in Beirut.
If the electoral law is worked out, it would help clear the way for a new president to be elected in parliament.
The two sides have agreed on General Michel Suleiman as a consensus candidate to succeed Emile Lahoud, the former pro-Syrian president, who stood down at the end of his term of office in November.
Lebanon has been without a president since, owing to differences between the majority and opposition over the makeup of a new unity government and proposed changes to the electoral law.
Tareq Mitri, Lebanon's acting foreign minister, accused the Hezbollah-led opposition of showing insufficient respect for the efforts of the Qatari mediators to find a compromise.
Samir Geagea, a prominent Christian leader in the majority bloc, said the dialogue had been dealt a "heavy blow" by the opposition.
He accused the opposotion of taking "matters back to square one".
Qatar has also proposed including a clause in the final statement of the talks, requiring all sides to denounce any resort to armed violence in internal Lebanese disputes.
Disagreements between the two sides over Hezbollah's weapons have proved an additional stumbling block in the talks.
The government representatives have insisted that Hezbollah's arms be on the agenda for the talks in Qatar, but Hezbollah's delegates said earlier this week that the issue is "not up for discussion".
Attempting a compromise, Akram Shehaieb, a Druze member of parliament, said the pro-government bloc wanted to address only the issue of the weapons used "against the Lebanese people in Beirut and the mountains" in recent clashes.
"The weaponry of the resistance is a Lebanese issue which will be debated in a [subsequent] dialogue led by the president in Lebanon," he said.
Hezbollah's weapons are a sore point in Lebanon. Most armed groups voluntarily disarmed after Lebanon's 1975-1990 civil war, but Hezbollah was allowed to keep its arms to resist Israel and has since built up a huge arsenal.
The Qatar-hosted talks follow an Arab-mediated deal that brought an end to a week of fighting, prompted by government moves to ban Hezbollah's private communications network and sack the security chief at Beirut airport, who was alleged to have ties to Hezbollah.