KATHMANDU (Reuters) - Nepalese Prime Minister Pushpa Kamal Dahal faced a crisis on Wednesday after a key ally in his multi-party coalition withdrew support, pushing his government into a minority in parliament four months after the coalition was formed.

The liberal Communist Unified Marxist Leninist (UML) party, which withdrew support and was the biggest group supporting Dahal's government since March, also said eight ministers it had nominated to the coalition would resign.

Party officials said UML and opposition Nepali Congress party, the two largest groups in parliament, would unite to form a new coalition and replace the one headed by Dahal.

"The new alliance is for stability," UML's Pradeep Gyawali told Reuters, without providing details.

Nepal, a natural buffer between China and India, has long been beset with factional fighting and politicians' egos that have prevented the formation of stable governments. There have been 13 since 2008, when Nepal became a republic and a 239-year monarchy was abolished.

Dahal, 69, a former Maoist rebel chief, has changed allies thrice since becoming prime minister after parliamentary elections in 2022.

His Maoist centre party said Dahal would not resign but would face a vote of confidence in parliament as required within 30 days.

Prakash Sharan Mahat, a spokesman for the Nepali Congress party, said UML chief K.P. Sharma Oli, 72, and Nepali Congress President Sher Bahadur Deuba, 78, would share the prime minister's post until the next election in November 2027.

(Reporting by Gopal Sharma; Editing by YP Rajesh and Bernadette Baum)

By Gopal Sharma