Balochistan National Party (BNP-M) chief Akhtar Mengal has been put under house arrest by the Hub administration as a protective measure.
The government accused the former Chief Minister of disturbing the law and order situation ahead of President Pervez Musharraf's visit to the province on November 30.
Mengal has been detained in a farmhouse in Sakran, which has been declared a sub-jail.
Pervez Zahoor, Deputy Inspector General of Police, Khuzdar range, said the provincial home secretary issued the detention order.
"Sardar Mengal has been detained under the Maintenance of Public Order-3," the Dawn quoted Zahoor as saying, adding that there was no restriction on his movement.
The paper quoted official sources as saying that Mengal was detained at around 2 pm on Tuesday after a heavy contingent of police and Anti-Terrorist Force personnel cordoned off the Lasi farmhouse in Sakran, some 16 km from the Hub town.
Meanwhile, reports said that Opposition senators have protested against the house arrest of Mengal.
A local daily reported that Dr Babar Awan raised the matter in the Upper House and said it was a violation of the Constitution to restrict free movement of any citizen.
He alleged Mengal's house arrest was part of the ongoing atrocities against the opposition leaders and workers in Balochistan.
Dr Abdul Maalik was quoted by a local daily as saying that there were no charges against Mengal and he was arrested just to block him from leading a protest march during Musharraf's visit to Balochistan.