An Iranian opposition leader who was being held against his will in a safe house belonging to the intelligence services has been transferred to his own home but remains under house arrest.

Mehdi Karroubi, a former presidential candidate in Iran's 2009 disputed election, returned home but a judicial official made clear on Monday that his house arrest has not been lifted.

"Two nights ago the authorities took my father back to his home in Tehran but security guards are still in control of his movements and communications," Karroubi's son, Mohammad Taghi, told the Guardian. "In his home, he is allowed to live with my mother who used to be under house arrest herself but is now free."

According to his son, Karroubi and his wife live on the second floor of their house while guards stay in the first floor. He is allowed to watch national television and has regular access to two state-run newspapers selected by the authorities, but not telephone or satellite channels. Immediate family members can visit him once a week with prior arrangements as in the past, his son said. Newspapers Karroubi is allowed to read include the conservative Ettelaat, Hamshahri and Jam-e-Jam, which do not have significant coverage of political news.

Iranian judiciary spokesman Gholamhossein Mohseni-Ejei told reporters on Monday that "the situation in which [Karroubi] is being held has not changed", according to the semi-official Isna news agency. "The change in the location of Karroubi's house has occurred in the past and is nothing new."

Karroubi and another former presidential candidate, Mir Hossein Mousavi, disputed the 2009 vote, which gave Mahmoud Ahmadinejad a second term in office, and alleged the results were rigged. In February 2011, when they called for street protests in solidarity with pro-democracy movements in Egypt and Tunisia, the security authorities placed them under house arrest and cut them off from the outside world.

Mousavi is being held in his own house in Tehran along with his wife, Zahra Rahnavard, also an outspoken critic of the regime.

Both men are suffering from medical complications partly due to their age: both are over 70 and were hospitalised a number of times last year. They have never been put on trial nor publicly charged, prompting some to argue that their house arrest is illegal. Senior hardliners have signalled that they could be freed if they repent but Mousavi and Karroubi have remained adamant that they have no regrets.

Since the election of Hassan Rouhani as Iran's new president, hopes have grown for their release and domestic media are now allowed to report on their predicament. The latest improvement in Karroubi's condition was even reported by the state English-language television, Press TV. A Press TV report, however, failed to clarify that Karroubi and Mousavi were under house arrest without being put on trial.