Thai police summoned eight senior members of Thailand's former ruling Pheu Thai party on Monday, for holding a news conference last week and broadcasting it on social media, in defiance of the military junta's ban on political activity.

The men, all of them former ministers, arrived at a police station in Bangkok on Monday.

It's believed they could face charges that include sedition, as well as charges under a computer crimes law.

They held the briefing last Thursday at Pheu Thai headquarters, despite being warned not to do so by police, just before it began.

The briefing criticised the junta's record in government since it took over in a bloodless coup four years ago, and came just ahead of the anniversary of the overthrow on Tuesday.

Pheu Thai is an incarnation of the political party set up by Thaksin Shinawatra which, under different guises, has won every Thai general election since 2001.

It was ousted from government by the military in 2014, following months of sometimes violent street protests in Bangkok.

Since then, the junta has kept a choke-hold on political life, banning party activities and outlawing any gathering for a political purpose, of five or more people.

Prime Minister Prayuth Chan-ocha has pledged to hold a general election next year, but there is widespread scepticism that it will happen.

The poll has been slated, then postponed several times before.

There is speculation that any charges against Pheu Thai might be used as a reason to dissolve the party ahead of the poll, thereby removing a major obstacle to the return of Prayuth as Prime Minister.