Rana Bhagwandas replacea Iftikhar Mohammed Chaudhry who faces charges.
A panel of judges is examining several allegations against Chaudhry, including one that he abused his position to obtain a senior police job for his son who was unqualified.
Opposition parties said police had arrested “hundreds” of supporters overnight before the protests on Tuesday.
“The Pakistan government’s promise not to intervene is little more than hot air”
Jim H, USA
In the eastern city of Lahore around 1,500 lawyers shouted slogans at the high court. They were outnumbered by around 4,000 police.
Another 300 lawyers rallied in the southern city of Karachi, around 400 in the central city of Multan and 250 in the northwestern city of Peshawar while there was a widespread boycott of court proceedings.
Opponents say Musharraf suspended Chaudhry to weaken the judiciary in a bid to remain army chief past 2007, when he is meant to give up the position under the constitution.
Musharraf is also expected to seek re-election for another five-year presidential term by the outgoing parliament ahead of national polls due late this year or early next – a move that could also spark legal challenges.