A human rights activist in Swaziland is challenging King Mswati III's decision to change the tiny southern African nation's name to the Kingdom of eSwatini.

Africa's last absolute monarch announced the new name in April at celebrations to mark the 50th anniversary of Swazi independence from Britain.

However, activist Thulani Maseko argued in a High Court submission that the decision undermined the constitution and was a waste of money, especially in a country with the world's highest HIV/AIDS rate.

He asked that the court set aside the decision as the product of the whim of the UK-educated monarch taken without any public consultation, court papers showed on Friday.

"Every citizen has a right to take part in the conduct of public affairs, directly or through freely chosen representatives," Maseko said in the papers.

Most of the landlocked nation's 1.5-million people eke out a living as farmers or migrant labourers in neighbouring South Africa. Swaziland holds elections every five years but political parties are not allowed to contest and the king appoints the Prime Minister.

The Attorney General's Office, which is named in the papers, has not yet responded to the submission.