Burma's opposition leader Aung San Suu Kyi has said that government censors are not allowing her party to criticise the previous military-run governments when it promotes its policies on state-run radio and television before next month's elections.

After decades of military repression, a nominally civilian government, elected last year, has been enacting reforms including releasing hundreds of political prisoners, relaxing media censorship and allowing Suu Kyi to stand as a candidate for the National League for Democracy party (NLD).

However, the military is guaranteed a quarter of the seats in the country's lower house while the remainder is dominated by the main pro-military party. Under an election law brought in by the previous regime, political parties are banned from making campaign statements harmful to the military. NLD spokesman Nyan Win said Suu Kyi's party broadcast, to be taped on Monday in the capital, Naypyitaw, had been approved, but a paragraph was excised under regulations that ban statements harming the military's image.

Her statement will be broadcast on 14 and 22 March. "The parts about the lack of rule of law and about the laws enacted by successive military governments to suppress the people were censored," Suu Kyi told US-funded Radio Free Asia on Saturday.

The 15-minute broadcast will be the first time the Nobel peace prize laureate has been given the opportunity to use the state media to promote her party's platform.

Suu Kyi campaigned on Sunday in the Mon State capital of Moulmein, 180 miles south-east of Yangon, where thousands of supporters greeted her. She has been barnstorming the country ahead of 1 April byelections, in which her NLD party will be contesting all 48 parliamentary seats at stake. Suu Kyi herself will be running in a constituency south of Yangon.

She told supporters her party had been established with the goal of having a democratic system take root in the country, protecting human rights and preventing the re-emergence of a military dictatorship. Burma was under army rule from 1962 until last year.

"Frankly speaking, these things have not yet been achieved," Suu Kyi said. "We are not fully enjoying human rights and the democratic system hasn't taken root yet. It is also still unclear whether a military dictatorship will emerge again or not."

Suu Kyi's party overwhelmingly won a 1990 general election, but the military refused to allow it to take power.