Kathmandu - Nepal's ruling Maoists have made slight gains in the by-elections at the expense of the opposition Nepali Congress, election officials reported Saturday. The Communist Party of Nepal (Maoists) won in two constituencies in Kanchanpur and Kaski districts in western Nepal, the Election Commission said.

It was also expected to win in Rolpa district in western Nepal which is a Maoist stronghold. However, vote counting had been delayed in the district due to technical reasons.

Voting was held for six constituencies on Friday, and of the five declared results, the Maoists won in two constituencies while the Nepali Congress, Communist Party of Nepal - Unified Marxist Leninist and the ethnic Madhesi Janadhikar Forum had won one seat each.

Vote counting was underway in Rolpa district and the results were not expected until Sunday.

Nepal's main opposition Nepali Congress suffered reverses in two constituencies which it previously held in Dhanusha and Kanchanpur districts.

The election was seen as the test of Maoist popularity since forming a coalition government in 2008.

The latest results are expected to boost the Maoist party as it prepares to enforce several controversial regulations, political analysts say.

The Maoists emerged as the single largest party in the 601 member constituent assembly after elections in April 2008, just two years after giving up armed insurgency.

The Maoists have however, come under growing criticism from its coalition members as well as the opposition Nepali Congress who accuse them of continuing violence, intimidation and extortion.

The constituent assembly is an interim legislature which is also tasked with drafting the country's new constitution. (dpa)