Renouncing violence has been a condition set by the parties for considering a proposed alliance with the rebels against King Gyanendra, who seized absolute power in February.
"The ceasefire is going to help widen the space for the peace process and we will try to enhance this space," said Mahesh Acharya of the Nepali Congress, on Sunday.
"We will take immediate steps to restore peace and turn the ceasefire into permanent peace."
The seven largest parties in Nepal have formed an alliance, led by the Nepali Congress, to restore democracy, but so far have shunned an offer by the rebels to join them in their fight against the king.
Leaders of the political alliance were meeting on Sunday to decide whether and when to begin talks with the rebels.
On Saturday, rebel leader Prachanda announced a three-month ceasefire, saying his fighters would not attack government or civilian targets during the period, but would defend their positions.
"Within this time the people's liberation army under our control would only retaliate if they come under attack. There will be no offensive action from our side," Prachanda, whose real name is Pushpa Kamal Dahal, said in a statement.
The elusive rebel leader said the move would provide an opening for peace in the Himalayan nation.
"It is the responsibility of the major political forces in the country to provide a political solution to the problems facing the country"
"It is the responsibility of the major political forces in the country to provide a political solution to the problems facing the country," he said.
Prachanda suggested there was a conspiracy to push Nepal towards becoming a failed state, prompting the rebels to take action to prevent the situation from deteriorating further.
Tulsi Giri, vice-chairman of the king's hand-picked cabinet, said: "We have only heard about the statement but have not received any more detail. We will first review the statement and only then react."
Rebel violence has escalated since King Gyanendra seized control of the government, a measure he said was necessary to quell an uprising that has left more than 11,500 dead.
The rebels claim to be inspired by Chinese communist revolutionary Mao Zedong and have been fighting for nine years to topple Nepal's monarchy.
Rebels have been trying to topple
Nepal's monarchy for nine years
They declared a ceasefire in 2001 and again earlier this year but negotiations with the government failed both times.
The rebels have insisted on an election for a special assembly that would draft a new constitution and decide whether the monarchy should be abolished.
The government, however, has demanded that the fighters give up their arms and join mainstream politics.