"Mangaluru Police Commissioner P.S. Harsha has advised Siddaramaiah not to visit the city till normalcy returns," police officer Guru Kamat told .
Mangaluru is about 350km west of Bengaluru on the southern state's coastal area.
The police notice in Kannada was sent to the former chief minister who sought permission to visit the city on Sunday, as it is under curfew after two persons died in police firing on protesters when they allegedly turned violent on Thursday.
Criticizing the police for not allowing him to visit Mangaluru, Siddaramaiah said it was his duty to assess the situation and console the bereaved families of the two victims. He said the police had denied permission to his chartered aircraft to land at the Mangaluru airport on Saturday.
"I decided to take a regular or commercial flight to Mangaluru on Sunday, as I have the right to visit the city as the opposition leader in the state assembly and shadow chief minister to study the ground situation," Siddaramaiah told reporters in Bengaluru.
Accusing the BJP government of suppressing his democratic right to visit the city for first-hand information on what triggered the violence and caused the police to fire on the protesters, Siddaramaiah said a delegation of his party leaders were denied permission to enter the city on Friday and sent back to Bengaluru in a hurry.
"We are living in an undeclared emergency situation @BSYBJP. Should insist @narendramodi to at least declare emergency officially & run 'Tuglaq Darbar' as they wish," tweeted 71-year-old Siddaramaiah.
The CAA grants Indian citizenship to Hindu, Christian, Sikh, Buddhist and Parsi refugee communities fleeing religious persecution from Pakistan, Afghanistan, and Bangladesh, and who entered India on or before December 31, 2014.
Terming the BJP government action against anti-CAA protestors, including imposing a ban order on them, as murder of democracy, Siddaramaiah said he need not learn lessons on law and order from the ruling party.
He said there was no firing or violence during his 5-year tenure (2013-18) as the state's chief minister.
( With inputs from IANS )