Myanmar's powerful military on Tuesday raised the spectre of staging a coup as it ramped up demands for an investigation into alleged voter fraud during last year's election, swept by Aung San Suu Kyi's ruling party.

The National League for Democracy (NLD) won November's poll in a landslide, but has been much criticised by rights groups for its disenfranchisement of voters in conflict-wracked regions.

The military-aligned opposition disputed the results, while the army has for weeks alleged widespread voter irregularities, claiming to have found 8.6 million cases of fraud.

Military spokesman Major General Zaw Min Tun on Tuesday renewed calls for the country's embattled election commission to provide final voter lists for cross-checking -- a demand that so far has not been met.

"Not resolving this in line with the law means this is a political crisis," he told reporters in Myanmar's capital Naypyidaw.

Zaw Min Tun added that military chief Min Aung Hlaing -- arguably Myanmar's most powerful individual -- has already pointed out "dishonesty and unfairness" during the election.

Myanmar's military spokeperson raised the spectre of staging a coup as it ramped up demands for an investigation into alleged voter fraud during last year's election
Myanmar's military spokeperson raised the spectre of staging a coup as it ramped up demands for an investigation into alleged voter fraud during last year's election AFP / Thet Aung

When pressed on the possibility of a coup, the spokesman refused to be drawn, but did not rule it out.

"We do not say the Tatmadaw will take power. We do not say it will not as well," said the spokesman, using the Burmese name for the military.

"What we can say is we will follow current existing laws, including the constitution."

The polls in November were the second openly contested elections since Myanmar emerged in 2011 after nearly 50 years of junta rule.

But the military still holds an outsized role in the country's politics, retaining control over key ministries thanks to a junta-scripted constitution which dictates an uneasy power-sharing agreement with de facto leader Suu Kyi.

She has not publicly responded to allegations of voter fraud but NLD spokesman Myo Nyunt said Tuesday a coup was not allowed under the current constitution.

"We will move forward peacefully according to the law," he told AFP.