Aung San Suu Kyi's opposition appeared on the verge of a landslide election win that could finally reset Myanmar after decades of army control Tuesday, as a top member of the ruling party said they had "lost completely".

The polls, the first contested by Suu Kyi's National League for Democracy since 1990, saw voter turnout hit around 80 percent as Myanmar's long-suffering people made their voice known at the ballot box.

The military ruled the country with an iron fist for half a century, killing, jailing and silencing dissenters and flat-lining the economy with madcap policies and rampant corruption, before stepping aside in 2011 in favour of a quasi-civilian regime.

Official results from Sunday's historic polls, drip fed to the public since Monday, showed major NLD gains.

By Tuesday evening the party had swept up 88 percent of the declared seats, taking 78 in the lower house and a further 29 in the upper chamber.

Suu Kyi said she believed that would play out into a healthy parliamentary majority.

"We probably will get between, around 75 percent in the union legislature," she told the BBC in an interview.

The ruling Union Solidarity and Development Party (USDP) meanwhile faced a rout after taking just a handful of those spots in the 440-seat house.

"Our USDP lost completely. The NLD has won," senior party member Kyi Win told AFP from party headquarters in the capital Naypyidaw.

"This is the fate of our country. Let them (the NLD) work. Daw Aung San Suu Kyi has to take responsibility now... we congratulate them anyway."

Kyi Win, a retired army officer who sits at the heart of party operations in the capital, said the NLD was poised to win a coveted majority in parliament.

But official victory for the NLD remained elusive, with election officials releasing results at just a trickle throughout Tuesday.

Voters worried

NLD voters remained confident of a major win, but were cautious of kickback from the still powerful army, whose stake in the future is guaranteed by a 25 percent bloc of reserved seats in parliament.

"I think the results will come soon, but I'm worried," said Ma Pyone, a vegetable seller in downtown Yangon.

"I don't know if the current government will seize power (if they lose) or not, but I hope they won't."

The NLD needs 67 percent of contested seats across both houses of parliament for a majority. But anything higher would bolster its parliamentary leverage against the army.

Suu Kyi's political ascent is also capped by the army-scripted constitution that bars anyone with foreign children from the presidency.

Her two sons, much of whose upbringing she missed while under house arrest in Yangon, are British.

A massive majority would strengthen her hand in selecting a favourable president, and she vowed before the election to be "above the president" in the event of an NLD win.

If the NLD is victorious it will inherit a country crushed by poverty, with several ethnic rebellions and religious intolerance simmering.

Suu Kyi will also have to work with the army, whose parliamentary bloc is flanked by a fearsome reputation.

'Not over yet'

There was scant early evidence that the election result would be warped by massive fraud, according to poll observers, but voters remained on guard after bitter experience of previous flawed polls.

The head of the European Union's monitoring mission, Alexander Graf Lambsdorff, praised authorities for doing a "good job" in holding the election across a vast and impoverished country.

"This election is not over yet" he said, but added the vote count was going on in a "transparent manner".

The NLD recorded a landslide in the last elections it contested in 1990 only for the army to ignore the result and double down on its repressive rule.

But in a televised statement before Sunday's election President Thein Sein said both the ruling party and the army will respect the result.

Buoyant red-clad supporters of Suu Kyi's NLD sang and danced for a second night on Monday outside the party base in Yangon, cheering each confirmed win as expectations of a landslide mounted.

But on Tuesday morning the big screen and loudspeakers, which 24 hours earlier carried an impromptu address by Suu Kyi, were suddenly removed.

Washington welcomed the "peaceful and historic" election but nonetheless urged caution until official results were confirmed.

Election officials said it could take days for the full results to be officially announced.