Burkina Faso president Roch Marc Christian Kabore, who was overthrown in an army putsch, has been "totally locked up", his People's Movement for Progress (MPP) party complained on Tuesday.
He had been moved from house arrest to his own home in the capital Ouagadougou in early April following the January coup.
But since then he has been "free neither to move nor to receive certain people and communicate", party chairman Alassane Bala Sakande told a press conference.
"It's the same as being totally locked up," he added.
"The MPP denounces in no uncertain terms the deprivation of liberty that president Kabore continues to face, four months to the day after the coup of January 24," the chairman said.
"Nothing justifies this denial of justice," he said, calling for Kabore's release "without delay or any condition".
The African Union, West African bloc ECOWAS and the United Nations have all called for him to be set free.
Kabore was toppled by officers disgruntled at his handling of a nearly seven-year-old jihadist insurgency that has claimed some 2,000 lives and forced 1.8 million people to flee their homes.
The junta, led by Lieutenant-Colonel Paul-Henri Sandaogo Damiba, says he has made the security crisis his priority, but after a relative lull in violence, a surge in attacks has claimed more than 200 lives.