If he carries it through, it would end eight years of military rule since he seized power in a bloodless coup. He backtracked on an earlier promise to resign from the army in 2004.
It would also meet a key demand of the international community outraged by his state of emergency, now well into its fourth week, despite his promise of free and fair general elections on January 8.
"My information is that he will take the oath as a civilian president on Thursday (local time)," Attorney-General Malik Mohammed Quayum said.
He said General Musharraf, who seized power in a bloodless 1999 coup and has often portrayed himself as his nuclear-armed nation's protector, would first resign as army chief before swearing himself in.
Last week the purged Supreme Court rubber-stamped Gen Musharraf's victory in an October 6 presidential election, clearing the way for him to serve a further five years in office.
Mr Quayum said the Defence Ministry was expected to issue a formal notification of his impending resignation from the army.
"We expect today, hopefully, the notification will be issued," Gen Musharraf's spokesman Rashid Qureshi said.
"If it is received today, then one can expect the handing over and taking over [as army chief] could take place tomorrow or the day after."
That would allow for the swearing-in on Thursday.
The oath would be administered by Pakistan's new chief justice, appointed after Gen Musharraf sacked his predecessor for refusing to endorse his November 3 imposition of emergency rule.
The general, a key US ally in the fight against Al Qaeda and the Taliban, has been under intense international pressure to end the emergency and hang up his uniform before becoming a civilian leader.
In the past two weeks he has orchestrated a series of legal steps to shore up his special measures and copper-bottom his presidency.
As well as brushing aside challenges to his re-election, the Supreme Court has dismissed complaints against emergency rule, using almost exactly the same arguments of growing Islamic militancy and a meddling judiciary.
Earlier, Gen Musharraf issued an edict declaring no court could ever overturn the legal basis for the emergency order and subsequent decrees, which included firing some of the nation's top judges.
He issued another edict which shifted the power to end emergency rule from the army chief - himself - to the president, also himself.
But Gen Musharraf is also under domestic political pressure.
The return of former Prime Minister Nawaz Sharif from exile means there are now two former premiers facing him, after Benazir Bhutto flew home a month ago.
They are consulting on a common anti-Musharraf strategy, which may include boycotting the January elections, although for the moment they are lodging their nomination papers pending a final decision. © 2007 Australian Broadcasting Corporation