Mynamar, also known as Burma, is to hold by-elections on 1 April that could see democracy leader Aung San Suu Kyi and her party enter parliament for the first time.
The elections are for 48 seats, most of which have been vacated by MPs who have become ministers .
Ms Suu Kyi officially registered her opposition National League for Democracy party a week ago and has already said she intends to stand in the polls.
But while her party has said it plans to contest every seat, an NLD spokesperson said the party had been given little time to prepare.
The BBC says the NLD has yet to complete all the formalities involved in applying for registration.
The NLD overwhelmingly won elections in Burma in 1990 but the military regime did not allow it to take power.
Ms Suu Kyi spent much of the next two decades in detention until she was released from house arrest a few days after a controversial general election in November 2010 - the first to be held in 20 years.
Her party boycotted that election and was then declared illegal.
The BBC says the military-backed but civilian-led government's decision to allow Ms Suu Kyi's party to register has already won cautious praise from international observers, including the US.