Burma's government is denying allegations of ballot tampering during last month's by-elections, which saw an historic victory for the opposition party of pro-democracy leader Aung San Suu Kyi.

Many in Aung San Suu Kyi's National League for Democracy complained of irregularities, including allegations that ballots in several towns were covered in wax that could be rubbed off to change the votes.

The state-run New Light of Myanmar on Tuesday said those claims were found to be “groundless” after an investigation in 10 towns found no evidence of ballot tampering.

The paper said the accusations could “harm the image” of Burma's closely watched by-elections, and said legal action should be taken against those making the complaints.

The NLD won 43 of the 45 of the available seats in the April 1 election. Aung San Suu Kyi, who was elected to parliament for the first time in the polls, was sworn into Burma's lower legislative house last week.

International observers said the polls were generally fair, but did reported some instances of voter and candidate intimidation, and said some voters were allowed to vote twice.