Maldives authorities on Friday prevented the former president who was ousted in February from leaving the island nation to visit his ill father in Bangkok, a party lawmaker said.
Mohamed Nasheed, 45, who resigned after what he alleges was a coup, is awaiting trial by a special court on charges of giving an illegal order when he was in office to have a judge arrested.
If convicted, he could be jailed or banished to a remote island for three years.
The Maldives, better known as a luxury holiday destination, has been rocked by violent protests over the past year in a stand-off between Nasheed's Maldivian Democratic Party and its opponents, who are now in power.
"We believe this is pure harassment and such behaviour towards a former president cannot be tolerated," Maria Didi, a MDP lawmaker, said.
Nasheed, who won the first free elections in the Maldives in 2008, was forced out after prolonged public demonstrations against him and a mutiny by police.
His trial has been suspended and his lawyers said he was granted leave to travel freely until January 5.
President Mohamed Waheed's spokesman was not immediately available to comment.