Parliament in Nepal is due to debate a call for the abolition of the country's 240-year-old monarchy.
The Maoists are demanding the abolition of the monarchy
The Maoist former rebels want a republic to be declared before constituent assembly elections.
Correspondents say the demand is likely to be rejected because it contradicts an agreement to leave the decision about the monarchy to Nepalese voters.
The Maoists are also insisting that the elections be held on a system of proportional representation.
Elections were postponed indefinitely after the Maoists left the interim coalition government last month.
The elections are a key element of a peace deal signed in 2006 that ended 10 years of Maoist insurgency.