Pakistan's fragile coalition government is facing a Monday deadline on reinstating judges sacked by former president Pervez Musharraf that could determine whether its major parties split.

Political infighting has weakened the ability to focus on militant violence - almost 100 people were killed in bombings in the past week - and leave the government in disarray ahead of the September 6 presidential election.

Seven militants were killed and three soldiers wounded in the latest violence in the troubled tribal areas along the Afghan border, security officials said on Sunday.

The party of ex-prime minister Nawaz Sharif has imposed a Monday deadline for hearing from its coalition partner, the Pakistan People's Party (PPP), on whether the judges will get their jobs back.

Critics say PPP leader Asif Ali Zardari, the widower of another former premier, Benazir Bhutto, fears their return could mean the end of an amnesty on corruption charges that brought the couple back to Pakistan in 2007.

Although the PPP has signalled it will agree to the reinstatement, it has been dragging its feet on the issue, which has threatened to fracture an already fragile coalition which took power only six months ago.

Zardari confirmed on Saturday that he would run for president in the September 6 poll triggered by Musharraf's resignation to avoid impeachment charges.

A resolution on the reinstatement of the 60 judges, who include the independent-minded former chief justice Iftikhar Muhammad Chaudhry, would require the PPP's support.

Musharraf's resignation and the race to replace him come amid a prolonged battle with Islamic militants who have carried out a series of suicide bombings and clashed with troops on the Afghan border.

A double Taliban suicide bombing at Pakistan's biggest weapons factory on Thursday, the deadliest ever attack on a Pakistani military site, has put fresh pressure on the coalition to end its bickering and focus on militant violence.

Sharif also wants the powers of the presidency reduced to prevent the next incumbent from dissolving parliament - a power created by Musharraf - and said he would back Zardari for president if this happened.

PPP deputy secretary general Raza Rabbani said on Saturday that the judges would be restored to office but declined to disclose a timeframe.

Sharif previously threatened to quit the coalition if they were not reinstated by Friday.

The former premier - who was ousted by Musharraf in a 1999 coup - had said representatives of the two parties would draft a resolution on restoring the judges over the weekend and then introduce it in parliament on Monday.

Sharif's party spokesman Siddiqul Farooq said the issue of whether Zardari would stand for the presidency was the PPP's "own decision," not that of the coalition partners, but reiterated its leader's demands on Saturday.

"We do not want a civilian president with the same powers that Musharraf had, mainly the power to dissolve parliament," Farooq said.

"Our top priority is restoration of the judges and we want it done on Monday," Farooq insisted, adding that the party would meet in Islamabad on Monday to discuss the latest developments.

Farooq on Sunday said that the future of the alliance depended on reinstatement of the judges.

"The party will decide its future course of action," Farooq added.

"The alliance is intact today but its future depends on the fulfilment of the promise Zardari made for the restoration of the judges," he said.

The deadlock has heightened the political instability in Pakistan some six days after Musharraf, a key US ally, quit office and as Western nations look for continuity after his departure.

The parties in the current ruling coalition defeated Musharraf's allies in polls held in February.