KATHMANDU, Jan. 23 (Xinhua) -- Nepal's Prime Minister Sushil Koirala on Friday expressed the regrets for failing to promulgate a new constitution within the deadline.

A day after the scheduled date, Koirala accused the opposition parties for the failure, saying the drafting was hampered by the " undemocratic culture" of some parties.

Political parties have earlier promised to deliver the new constitution before January 22.

Koirala said there is a need of consensus among the major stakeholders of political forces.