Somkiat Pongpaiboon turned himself in at the Criminal Court on Friday after an arrest warrant was issued when the former co-leader of the People's Alliance for Democracy (PAD) failed to attend an Appeal Court ruling.
After reporting, Mr Somkiat told reporters he had no intention of evading the court's judgement on charges of illegally occupying Government House from Aug 26 to Dec 3, 2008.
The Appeal Court last Monday ordered his arrest after rejecting his lawyer's explanation that Mr Somkiat was sick and unable to be present at its scheduled judgement in the case. His client was suffering from headaches, vertigo and vomiting, he said.
The court rescheduled judgement day to July 24.
Mr Somkiat reported to the court on Friday with medical certificates from three hospitals testifying to his illness.
In 2015 the Criminal Court sentenced Mr Somkiat and five other PAD members to two years behind bars for leading thousands of yellow-shirt protesters to seize and occupy the prime minister's offices during their protests to oust then prime minister Samak Sundaravej and his successor Somchai Wongsawad.
The other defendants on the case brought by state prosecutors are Sonthi Limthongkul, Chamlong Srimuang, Pibhop Dhongchai, Somsak Kosaisuk and Suriyasai Katasila. All six were earlier released on bail.
Prosecutors put the cost of repairing damage to the occupied building and grounds at 6 million baht.