With just five days remaining for expiry of time limit to draft a new constitution, major parties in Nepal on Tuesday agreed to extend the constituent assembly's tenure by another three months.

The decision was taken at a meeting of Maoists, Nepali Congress, Communist Party of Nepal (Unified Marxist Leninist) and the conglomeration of Madhesi parties at Prime Minister Baburam Bhattarai's official residence.

Nepal's constitution writing deadline expires on May 27 and there is no consensus among parties on several crucial issues - like ways to restructure the country into federal units.

"We will try and arrive at a consensus on all issues within the deadline, but if we fail to do that, we will need more time to draft the constitution. Hence the decision was taken," said Maoist vice-chairman Narayan Kaji Shrestha.

The decision was later endorsed by the cabinet and a bill to amend the interim constitution to extend the deadline was registered with the constituent assembly secretariat.

"Efforts are still on to complete the task on time. But to ensure that there is no constitutional crisis if the deadline is not met, we agreed to the extension proposal," said Nepali Congress leader Bimalendra Nidhi.

Nepal's constituent assembly was created in 2008 with a two-year deadline to formulate a new statute. But the task has remained incomplete due to power struggles and differences among parties.

Till date there have been four extensions of the deadline.