Reports from Fiji say the wherabouts are unknown of a nationalist politician, Peceli Rinakama, who was last seen on Friday.
Mr Rinakama, who was once a member of parliament, was reportedly seized by soldiers and sources say it is not known where he has been taken.
Attempts to get information from the interim government have been unsuccessful.
During the recent trial of eight men accused of plotting to kill the interim prime minister, a witness said that Mr Rinakama was gathering ex-military personnel for the cause.
Mr Rinakama was also accused of being involved in the plot when the now convicted conspirators were arrested in 2007.
But he was released in late 2007 and charges against him were dropped.
Mr Rinakama had been jailed in 2004 for joining George Speight's failed rebel administration in 2000.