The swearing-in of veteran leader G P Koirala as prime minister of Nepal following revival of Parliament may be slightly delayed on Friday due to his illness.

"The 84-year-old Nepali Congress chief's health is improving and he may be sworn-in today but the time is not fixed," his nephew and Nepali Congress member Sekhar Koirala said.

• The Nepal Crisis 

Nepalese Parliament will meet for the first time on Friday in four years under pressure from Maoist rebels and the Seven Party Alliance.

Koirala was on Thursday appointed by King Gyanendra as prime minister as recommended by the SPA that spearheaded weeks of pro-democracy movement in the Himalayan Kingdom.

Koirala would be occupying the top post for the fifth time in his career.

He was the first elected prime minister in 1991 after the 1990 people's movement.

He was to address a public meeting on Thursday, but did not do so as he was suffering from bronchitis, Nepali Congress spokesman Krishna Sitaula had said.

Koirala was on Thursday also unanimously elected as the leader of Nepali Congress Parliamentary Party.

The SPA had endorsed his name for the top post on Monday after the King's proclamation to reinstate Parliament.

Brightening prospects of return of peace and democracy in Nepal, Maoists on Wednesday night announced a three-month unilateral truce, a move immediately welcomed by the SPA which vowed to remove the terror tag on the rebels and hold negotiations with them to bring them into political mainstream.

The Maoists, however, stuck to their demand for Constituent Assembly that would draft a new Constitution which is likely to limit the powers of the King in governance.

The rebels have announced that they would hold their first public meeting in Kathmandu on Friday.