Pro-democracy groups led by South Africa's Economic Freedom Fighters (EFF) have given Eswatini's King Mswati III a year to abdicate.

This was said as the EFF led the blockage of the Ngwenya (Oshoek) and Golela border posts for six hours on Tuesday in solidarity with the Eswatini chapter of the party's call for democracy and human rights.

The border blockage on the king's 54th birthday was to make sure "he's broke on his birthday".

"Today is Mswati's birthday. We are presenting him with a special gift. He is used to taking taxpayers' money via the gates and spreading it for his lavish lifestyle with his wives and children. Today we are here to suppress the economy sustaining the livelihood of the regime," Mthokozisi Makhunga, the EFF deputy president in Eswatini, told journalists.

With growing calls for the last absolute monarch in Africa to step down, the crisis in Eswatini had been tabled at the SADC extraordinary organ troika.

Early this month, the issue along with Mozambique's Islamic extremism insurgency was due for review in Pretoria at the SADC Summit, however, Eswatini was removed from the programme because of the unavailability of the presidents of Botswana and Mozambique. The summit segment had to be deferred to a later date.

However, the delay was not holding back pro-democracy lobbyists' push for change and they vowed that King Mswati III would not be in power this time next year.

"We are saying this should be the last birthday that the king celebrates as a king because the people of Swaziland are tired and the people of Swaziland want democracy and freedom. We cannot see a co-existence between the people of Swaziland and the king because the king has killed many of our people," said Bonginkosi Dlamini, the United eSwatini Diaspora convener.

The EFF demanded that the King must "account for human rights violations. We also want justice for the 150 Swazis killed by Mswati."

Godrich Gardee, EFF secretary-general, addressed the crowd at the Ngwenya border, saying what they were doing was showing the king that "his days are numbered".

The People's United Democratic Movement (Pudemo), the largest opposition party in Eswatini, commended the EFF for its resolve in calling for change.

"All of us are fighting for a humane society, we are fighting for a just society... we take this opportunity as Pudemo to say salute to the EFF both in South Africa and Swaziland," said Pudemo leader Mlungisi Makhanya.

The Eswatini government's ministry of home affairs said there had been "disturbances" at the Ngwenya border post, but that things had since returned to normal.

"The ministry of home affairs notifies cross-border travellers that there was disturbance at Ngwenya border post earlier today. However, the situation has subsided and the border is now operating normally. Any inconvenience caused is deeply regretted," the department said.