Amir, who is playing domestically after he was banned from international matches for five years in a 2010 spot-fixing scandal, allegedly cursed at Iqbal during the match on Monday.
Iqbal, according to game footage, responded by calling Amir a “thief”, provoking the bowler into another verbal attack.
A spokesman for the Pakistan Cricket Board (PCB) confirmed action had been taken against Amir.
“Amir has been fined 50 percent for misbehaviour and 100 percent for the verbal attack,” the spokesman told AFP. “Iqbal was also fined 50 percent of his fee for indiscipline.”
Amir, along with then captain Salman Butt and Mohammad Asif, was charged for orchestrating deliberate no-balls during a Test against England at Lord’s in 2010.
The trio, along with their agent, were jailed for several months in 2011.
Amir was allowed to play in domestic matches from January this year after an amendment in the International Cricket Council (ICC) code which allowed all banned players to play in domestic matches a few months prior to their ban ending.
He has been in great form, taking 34 wickets in just four matches.
The ICC lifted sanctions on all three players last month.