Sweeping restrictions on political parties and campaigns were imposed after the military took power in a coup four years ago.

On Friday, the junta said there would be a "relaxation" on the ban in a statement published in the Royal Gazette.

Parties will now be permitted to elect their leaders, recruit new members, establish branch offices and hold general party meetings if they are able to summon at least 250 members.

But a ban will remain on political campaigns and gatherings of more than five people.

"Political parties can communicate with their members electronically, but that type of communication must not be a considered as a form of political campaigning," the statement said.

The National Council for Peace and Order (NCPO) -- the junta's formal name -- and the Election Commission will have the authority to rule on whether any political communications were "disrupting public order".

The junta has repeatedly postponed elections, but King Maha Vajiralongkorn this week endorsed two bills that cleared bureaucratic hurdles to a much-anticipated poll.

An nationwide vote is required to take place by May and senior military leaders have floated a February 24 election date.

Opposition parties said the NCPO should never have introduced the ban in the first place.

Pannika Wanich, the spokesperson of the upstart Future Forward party -- which has set Thailand's political scene abuzz with its pro-democracy platform -- said her party would not adhere to the ban's restrictions.

"We declared a long time ago that we will not accept any unjustified laws," Pannika said, adding that her party expects to be officially certified by the Election Commission next week.

"We will do whatever a political party can do," she said. "We are not waiting for the NCPO to ease off the ban."

- 'Political bullying' -

Pichai Natipthaphan, a member of the now-toppled Puea Thai Party and former minister in the government of Yingluck Shinawatra, said the remaining constraints on political activities were "not practical".

"It restricts the rights of people and it could lead to political bullying," he said of the new rules.

The Shinawatra clan, a powerful and wealthy family, has won every Thai general election through its affiliated parties and proxies since 2001.

But coups have pushed Yingluck and her older brother Thaksin -- another former prime minister -- out of power and into self-exile to avoid jail terms from corruption charges.

The military has long hated the Shinawatras, accusing them of harnessing a toxic brand of populist politics.

Junta leader Prayut Chan-O-Cha has insisted that he has no interest in politics, but critics claim the military's protracted rule since Yingluck's 2014 ouster is evidence of his future electoral ambitions.

In recent months, the gruff former general has been showcasing a softer side through public appearances and photo opportunities.

Earlier this week he met with Japanese girl pop sensation "AKB48" at Government House, waving a neon glow-stick as they performed.