The NCP and NCP-UML
together drafted Nepal's Constitution of 1990, which provides for constitutional monarchy and parliamentary democracy in the Himalayan kingdom.
was the second-largest political party in Nepal before the parliament was dissolved.
The Maoist NCP-UML
is currently waging an armed struggle to topple the country's constitutional monarchy and end multiparty rule.
, with 70 seats in Nepal's 205-member parliament, is the principal opposition party.
, the largest opposition party in the Nepalese parliament, is spearheading protests calling for the ouster of Koirala on corruption charges.
Hundreds were injured as police used their batons to charge at demonstrators and to disperse them in different cities," the NCP-UML
said in a press release.
General Secretary Madhav Kumar Nepal said a parliamentary investigation into the alleged irregularities is essential if the country's future elections are to be free and fair.
The NCP won 110 seats against 68 seats for the NCP-UML
in polls described as ''fair and peaceful'' by international observers.