A court trying former military ruler Pervez Musharraf for treason Thursday ordered him to appear in person on January 16, after considering a medical report on his heart complaint.

The ruling grants the 70-year-old, currently in a military hospital, a week's respite in the case which has gripped the nuclear-armed nation for the past fortnight.

He has yet to appear in person before the specially-convened three-judge tribunal, missing hearings due to security fears and lately a health scare.

He was was rushed to the Armed Forces Institute of Cardiology (AFIC) in Rawalpindi, which borders Islamabad, on his way to the tribunal last week, and has remained there ever since.

After considering a medical report -- which diagnosed the former commando with triple-vessel coronary artery disease -- the court ordered Musharraf to appear on January 16.

Another hearing is due in the case on Friday, when judges will consider certain procedural matters.

Thursday's hearing came on the same day that Musharraf's successor as president, Asif Ali Zardari, appeared before an anti-corruption court over graft allegations dating back to the 1990s.

Musharraf's camp says the treason allegations, which relate to his imposition of emergency rule in November 2007, are politically motivated and his lawyers have challenged the authority of the tribunal.

His sudden health scare was met with scepticism by some observers, and rampant media speculation that his departure as part of a face-saving deal to avert a civil-military clash could be imminent.

Rumours have circulated for months that a backroom deal would be struck to whisk him overseas to avoid a destabilising clash between the government, which brought the charges, and the powerful armed forces.

But the former commando has said he wants to stay and fight the charges.

Aside from the treason allegations, Musharraf also faces trial over the assassination of former prime minister Benazir Bhutto, the death of a rebel leader, a deadly raid on a radical mosque and the detention of judges.