Nepal's Prime Minister Pushpa Kamal Dahal is to reshuffle his government in the latest shakeup of alliances following a rift with his coalition partner, officials said Monday.

Dahal's Maoist Centre party is expected to push out the centrist Nepali Congress party and rebuild a leftwing coalition with its old ally, the Communist Party Nepal-Union Marxist Leninist (CPN-UML).

"The prime minister has informed the president on the restructuring of the cabinet," Dahal's press secretary Govinda Acharya told AFP.

Dahal, 69, an ex-Maoist guerrilla better known by his nom de guerre Prachanda or "the fierce one", leads the Maoist Centre party.

It is the third largest party with 53 seats in the 275-member parliament, of which a government must command at least 138 seats.

The Maoists have dominated Nepal's politics for more than 20 years after waging a decade-long insurgency against government forces that claimed more than 16,000 lives.

The civil war ended in a 2006 peace deal, which saw rebel leader Dahal become Nepal's first post-war prime minister.

The three main parties -- the Maoists, CPN-UML, and the Nepali Congress (NC) -- have since monopolised politics, forming varying brittle coalitions with one another.

"The prime minister has changed coalition partners twice in his short tenure so the government fails to be stable," senior political journalist Binu Subedi said.

"New ministers will have their own demands, so it will not be easy for him to work."

Dahal allied with the Nepali Congress after general elections in 2022, following a rift with the CPN-UML over a presidential candidate.

But he later switched his alliance back to the CPN-UML after facing difficulties working with the Nepali Congress, his press secretary Acharya said.

Also expected to join the latest coalition is the National Independent Party, which shocked many to become the fourth-largest party in its first run, holding 21 seats.

Subedi told AFP that Dahal was preparing the ground for the next elections.

"This alliance creates a basis for an election environment, where left-leaning parties will be on one side", he said.