The parliament had been due to give its formal approval to the deal reached Friday under which the main political parties agreed to give the Maoists five portfolios in a new cabinet.

But political wrangling over cabinet hierarchy forced a postponement of the parliamentary sitting until Sunday.

Nepal's seven main political parties and the former rebels met in the prime minister's residence on Saturday to sort out the differences.

The row did not jeopardise the decision to admit the Maoists into the new interim government, said Prakash Sharan Mahat, a lawmaker from the Nepali Congress (Democratic) party.

"We will meet tomorrow at 8:00 am (0215 GMT) and sort out these differences and we will go to parliament around 11:00 am (0515 GMT) tomorrow (Sunday) to formalise the cabinet," Mahat said.

The parties were at odds over who should hold the most senior positions in the cabinet. One of its tasks will be steering the Himalayan nation to new elections this year.

"The meeting has been postponed until tomorrow morning because the Nepali Congress and the Communist Party of Nepal (Unified Marxist-Leninist) could not reach agreement regarding the ministerial hierarchy in the interim government," said Dev Gurung, a Maoist leader.

"We don't have any major differences over the structure of the interim government," Gurung added.

Under the new government deal reached Friday, veteran Prime Minister Girija Prasad Koirala -- the leader of the Nepali Congress Party and architect of the peace process -- retains his position as leader of the government.

Koirala's party will also hold the key defence, home and finance ministries, while the Communist Party of Nepal (Unified Marxist Leninist) -- Nepal's second largest party -- will hold the foreign ministry.

The Maoists, who are still classed by the United States as a "terrorist" organisation, will head the ministries of information, local development, planning and works, forestry, and women and children.

"This is our first step in achieving the goal of establishing a new Nepal," said Maoist second-in-command Baburam Bhattarai.

The deal brings the leftists, who want to remove embattled King Gyanendra as head of state and become a republic, into government for the first time.

"This is a major achievement for our party," said Bhattarai, whose members are still morphing from a life of guerrilla warfare to mainstream politics.

The deal to include the Maoists capped months of discussion over power sharing following last November's historic peace accord, which ended the civil war that claimed at least 13,000 lives.

Prachanda, the Maoist leader, and Bhattarai will not take ministerial portfolios, the Maoists have said.

Under the next step laid out in the peace plan, the new interim government will organise elections for a constituent assembly in June to decide the future of the landlocked country.