A pro-democracy activist in Swaziland has challenged the king's decision to change the country's name.

In April, King Mswati III, one of the world's last-remaining absolute monarchs, unexpectedly announced he was changing the country's official name to the Kingdom of eSwatini.

The activist, Thulani Maseko, argued in papers submitted to the High Court that the decision was invalid because there had been no prior public consultation.

He said the decision was whimsical and a waste of money in a country with serious health problems.

The government has not yet responded to the challenge.