Libya's National Transitional Council (NTC) will hold fresh talks Saturday on forming a new government, amid doubts on whether disagreements that prevented a deal last week can be overcome.

On the ground, NTC fighters were delaying final assaults on fugitive ex-leader Muammar Gaddafi's two remaining bastions — his coastal home city of Sirte and the desert town of Bani Walid.

Speaking in the NTC's eastern headquarters of Benghazi, a council official said the meeting would also hear a report from NTC leader Mustafa Abdel Jalil about his talks this week in New York ahead of the UN General Assembly.

The birth of a new government had been due last Sunday, but was postponed indefinitely because of haggling over portfolios.

One official insisted Saturday's meeting would be "decisive," but another expressed doubts that differences could be overcome.

"There is still no agreement on the composition of the government or the number of its members," said the sceptical official. "There are a lot of proposals," he said, and while there could be a deal, "I fear we will not reach one given the current situation."

NTC number two Mahmoud Jibril, speaking in New York on Wednesday, said Libya would have a new government "in a week, 10 days maximum."

After talks failed on Sunday, Jibril said much had been achieved and that he expected consultations to be "over quickly".

At the time, there were expectations that Jibril, a former Gaddafi official, would keep his post as interim premier, while Ali Tarhuni was touted to become vice president in charge of economic affairs.

The defence portfolio was expected to go to Osama Al-Juwili and oil to Abdel Rahman Bin Yezza.

The NTC is also expected to look into getting women and young people into major roles as deputy ministers and directors general of ministries.

On the ground, desperate residents were fleeing Sirte Friday, as NTC fighters probed the city's eastern outskirts in anticipation of a final assault.

A commander near Sirte said pro-Gaddafi forces were targeting residents as they fled, with one fighter killed and a packed family car destroyed when their convoy was hit.

NATO said it was nearing the "final phase" of its air war in Libya, and said its only key hits on Friday were in the Sirte area — a command and control centre, an ammunition dump, an anti-aircraft gun and armed vehicles.

"Our fighters are in control of the eastern gate of Sirte," commander Ahmed Zlitni told AFP.

"They are two kilometres (1.2 miles) ahead of the gate and holding positions there. Technically we can say that we entered Sirte from the east," Zlitni said, adding that the fighters "did not face any resistance".

"Three to four brigades have entered through the eastern gate," confirmed commander Mohammed Al-Marimi.

Asked why NTC fighters were delaying the final assault, commander Osama Muttawa Swehly told AFP on Friday: "We're trying to get the families out. We are averaging between 400 to 500 cars a day. We are basically trying to starve (the Gaddafi forces) out."

"We are giving the families every chance to get out. Once that stream turns into a trickle then stops, then it will be time to act."

Meanwhile, some five kilometres outside Bani Walid, an AFP correspondent said troops loyal to Gaddafi were rocketing an NTC position.

He spoke as a doctor said fighting had claimed the lives of 30 interim government fighters in the battle for Bani Walid, 180 kilometres southeast of Tripoli. The NTC's northern front commander said another 50 had been wounded.

There has been intermittent fighting since 10 September, when the NTC launched its first assault and then withdrew after encountering fierce resistance.

When rebel fighters stormed and captured Gaddafi's Bab Al-Aziziya headquarters in Tripoli on 23 August, they found no trace of the strongman, who has since made several broadcasts claiming he is still in Libya.

While Libya's new authorities do not know where Gaddafi is, they are focused on taking Sirte and Bani Walid, two places where some think he might be. But reports have also emerged that he may be in the south.

"General Belgasem Al-Abaaj, who we captured on Monday, said that Gaddafi had contacted him by phone about 10 days ago, and that he was moving secretly between (the oases of) Sabha and Ghat," an NTC commander, Mohammed Barka Wardugu, told AFP.

Abaaj had said Gaddafi "is helped by Nigerian and Chadian mercenaries who know the desert routes," added Wardugu, spokesman for the Desert Shield Brigade.

Gaddafi's daughter Aisha said her father was well and fighting on the ground.

"Remain reassured, your great leader is doing well. He carries weapons and is fighting on the fronts," she said in a telephone message aired by Syria-based Arrai television, which regularly broadcasts comments from Gaddafi or his family.

"You can be proud of your leader," she said, addressing the "resistant people" of Libya.

Aisha Gaddafi, who fled to Algeria with her mother and two brothers late last month, called on the people to "rise" against the new rulers, saying NTC members were "traitors who have broken their oath of allegiance" to Gaddafi.