Tropical Myanmar has a long history of military rule, but the generals took a back seat for a decade of civilian-led reforms.

That ended in a 2021 military coup when democratic figurehead Aung San Suu Kyi was detained, civil war broke out, and the country descended into a humanitarian crisis.

The election's third and final phase opened in dozens of constituencies across the country at 6 am on Sunday (2330 GMT Saturday), just a week shy of the coup's five-year anniversary.

AFP journalists saw polling open in the second city of Mandalay and in Yangon's Hlaingthaya township -- the site of a bloody crackdown on anti-coup protests five years ago.

The military has pledged that the vote will return power to the people, but it is not being held in wide areas of the country carved out by rebel groups.

With Suu Kyi sidelined and her hugely popular party dissolved, democracy advocates say the ballot is stacked with military allies.

"I don't expect anything from this election," a 34-year-old Yangon resident told AFP, requesting anonymity for security reasons.

"I think things will just keep dragging on."

The Union Solidarity and Development Party (USDP) -- packed with retired officers and described by analysts as a military puppet -- won more than 85 percent of elected lower house seats and two-thirds of those in the upper house in the first two phases of the poll.

A military-drafted constitution also reserves a quarter of seats for the armed forces in both houses.

The combined parliament will pick the president, and junta chief Min Aung Hlaing has not ruled out taking the role.

Analysts say the military is stage-managing the poll to give its rule a veneer of civilian legitimacy.

The anonymous Yangon resident, feeling pressure to participate, pledged to cast her ballot for "any party except the USDP".

"I know what the final result will be, but I want to mess things up a little with my vote," she said.

Official results are set to be released late this week, but the USDP could claim victory as soon as Monday.

Suu Kyi's National League for Democracy party thrashed it in the last elections in 2020, before the military seized power on February 1, 2021, making unfounded allegations of widespread vote-rigging.

"Electoral fraud is a serious and disgusting issue in a democracy," Min Aung Hlaing said on state media on Tuesday.

Nobel Peace Prize laureate Suu Kyi, 80, remains detained incommunicado at an unknown location on charges rights monitors dismiss as politically motivated.

- 'Not safe at all' -

The military has long presented itself as the only force guarding restive Myanmar from rupture and ruin.

But its putsch tipped the country into full-blown civil war, with pro-democracy guerrillas fighting the junta alongside a kaleidoscope of ethnic minority armies which have long held sway in the fringes.

Air strikes are frequent in some regions, others enjoy relative peace, while some zones are blockaded, haunted by the spectre of starvation.

Polling was called off in one in five lower house constituencies, but some frontline locations are set to vote Sunday.

"Candidates still haven't held any campaigning because of security," complained one parliamentary candidate, speaking on condition of anonymity for security reasons.

"It's not safe at all to travel," they said, estimating only one in 10 polling stations would be able to open in their constituency.

There is no official death toll for Myanmar's civil war and estimates vary widely.

But monitoring group ACLED, which tallies media reports of violence, estimates more than 90,000 have been killed on all sides.

The UN says nearly half of Myanmar's 50-million population now live in poverty.

Meanwhile, more than 400 people have been pursued for prosecution under stark new junta-tailored legislation forbidding "disruption" of the election.

It punishes protest or criticism with up to a decade in prison, and arrests have been made for as little as posting a "heart" emoji on Facebook posts criticising the polls.

Turnout in the first and second phases of the vote were just over 50 percent, official figures say, compared to roughly 70 percent in 2020.