The chairman of the Swaziland (eSwatini) political party Sive Siyinqaba was questioned by police amid a fear he might be charged with sedition or terrorism.
Musa Nkambule, who is also a former government minister, was held for three hours and questioned by eight officers in Manzini on Tuesday, Eyewitness News in South Africa reported.
He was accompanied by his lawyer Thulani Rudolf Maseko.
It followed an official denial from the Swaziland government that Nkambule and three others were wanted for questioning on treason charges.
Nkambule had recently written a statement on behalf of his party that criticised King Mswati III, Swaziland's absolute monarch, for buying a fleet of 15 luxury Rolls-Royce cars for himself and his wives which were estimated to have cost US$6 million and the purchase of a fleet of 126 BMW cars and motorbikes for 'escort duties'.
The statement read in part, 'Sive Siyinqaba holds the view that someone [King Mswati] is on a suicide mission; unfortunately, he wants to sink with the whole country. We think it is time we say, we would rather remain afloat than to sink with you. High volumes of hundreds of millions in foreign exchange have been siphoned from the country to be spent in countries that need them less, in the form of competitive royal trips that we witnessed this year.'
Eyewitness News quoted Maseko saying, 'If they do believe the statement that Mr Nkambule made undermines the authority of the king, they can move against you with sedition or even terrorism.'
He said police confiscated Nkambule's cellphone.
He added, 'They want to see what conversations he has had and they will see if they can charge him.'
Eyewitness News reported, 'Maseko said while police insisted their intention was not to arrest Nkambule, they wouldn't be surprised if they go back on their word or go as far as charging him with treason.'
The Swaziland News, an online newspaper, quoted Maseko saying, 'We went there in the morning together with his wife and they confirm to have raided his home, they then requested to speak to him privately. Thereafter, he was released, hence we are waiting for their feedback tomorrow if they charge him or not.'