Kathmandu: Fresh tensions erupted between Nepal's Maoists and the seven-party government over power sharing, hours after the guerrillas joined parliament, signifying a formal end to their decade-old armed uprising.

The three major parties in the government and the communist rebels are now deadlocked over the key posts in the new parliament as well as the new government that will be formed after the Maoist disarmament is complete.

Prime Minister Girija Prasad Koirala, who heads the Nepali Congress, the biggest party in the new house with 85 legislators, is scheduled to begin negotiations with Maoist supremo Prachanda and other senior leaders Wednesday.

The Maoists are now the second biggest party, along with the Communist Party of Nepal-Unified Marxist Leninist (UML), with both holding 83 seats each.

With the rebels' entry in the 330-seat house, deposed premier Sher Bahadur Deuba's Nepali Congress-Democratic has fallen to third place with 48 legislators.

The current Speaker Subhash Nembang is from the UML. His appointment came after a fierce tussle with Deuba's party last year who finally had to settle for the post of deputy speaker.

"Everything will be changed," Maoist chief Prachanda told the media on the eve of his party joining parliament. "There will be a new speaker and deputy."

The eight parties failed to reach an agreement on the two posts Monday, when the old house was dissolved and a new one convened. The tussle is likely to increase once the Maoists join the government.

"We have a verbal understanding that Koirala will remain prime minister in the new government but it is not irreversible," Krishna Bahadur Mahara, newly appointed chief of the Maoists' parliamentary party, said.

Reports say the Maoists want the post of deputy prime minister if they can't get the speaker's post.

Currently, Nepal has two deputy prime ministers -K.P. Oli, a UML member who is also foreign minister, and Amik Sherchan from People's Front Nepal, who is also health minister.

 It remains to be seen if the new government will have a third deputy prime minister or if one of the current ones will be axed.

The media has already started speculating that Oli will be replaced by Mahara. Or else, the rebels will jockey for the home minister's portfolio.

Besides the disagreement among the parties, there are intra-party disputes as well.

Media reports Wednesday said Koirala's influential nephew Dr Shekhar Koirala, dubbed the shadow Prime Minister because of his meteoric rise in the party, is fuming at not having been nominated to the new parliament.

Koirala's party sent 10 new MPs to the house Monday, including his daughter Sujata Koirala. However, the list did not include Shekhar Koirala or another party stalwart, former spokesperson Arjun Narsingh KC.

There is fresh dissent in Deuba's party as well over the nomination of new MPs. Some senior members are irked that the former premier was given a free hand to choose the legislators.

The new disagreements revive the memory of last year's discord when the seven-party alliance was at loggerheads over the naming of ministers, forcing Koirala to halt his cabinet expansion for several weeks.