Myanmar's ruling junta on Friday announced tough requirements for parties to contest an election this year, including a huge increase in their membership, a move that could sideline the military's opponents and cement its grip on politics.

Myanmar's top generals led a coup in February 2021 after five years of tense power-sharing under a quasi-civilian political system that was created by the military, which led to a decade of unprecedented reform.

The country has been in chaos since the putsch, with a resistance movement fighting the military on multiple fronts after a bloody crackdown on opponents that saw Western sanctions re-imposed.

The military has pledged to hold an election in August this year. An announcement in Friday's state media said parties intending to compete nationally must have at least 100,000 members, up from 1,000 previously, and commit to running in the election in the next 60 days or be de-registered as a party.

The rules favour the Union Solidarity and Development Party, a military proxy stacked with former generals, which was trounced by Aung San Suu Kyi's National League for Democracy (NLD) party in 2015 and 2020 elections.

The NLD was decimated by the coup, with thousands of its members arrested or jailed, including Suu Kyi, and many more in hiding.

Richard Horsey, senior adviser to the International Crisis Group, who was based in Myanmar for 15 years, said the rules aimed to restore a political system the military can control.

"Parties are going to be either too scared, offended at the sham that the election is, or it will just be too expensive for them to mount a nationwide campaign in that kind of environment. Who would fund a political party right now?" he said.

"This whole exercise is something to perpetuate military rule. It's a piece of theatre. It doesn't have to work, because they've decided what the outcome will be."

The junta says it is committed to democracy and seized power because of unaddressed violations in a 2020 election won in a landslide by the ruling NLD.

The NLD in November described the election as "phoney" and said it would not acknowledge it. The election has also been dismissed as a sham by Western governments.

(Reporting by Reuters Staff; Writing by Martin Petty and Kanupriya Kapoor; Editing by Nick Macfie)