The 31-year-old, who returned to the sport earlier this month after successfully appealing against a two-year ban for doping, was leading Islamabad Leopards in a national Twenty20 contest on Tuesday night.
"Akhtar refused to wear a logo of the Pakistan Cricket Board (PCB) sponsor and, as a breach, match referee Anwar Khan fined him 10,000 rupees ($166)," PCB spokesman Dr Ahsan Malik said on Wednesday.
Akhtar, who has played 42 Tests and 133 one-day internationals for Pakistan, is currently featuring in Pakistan's tune-up camp for next month's tour of South Africa.
The Court of Arbitration for Sport in Switzerland is next week expected to hear an appeal by the World Anti-Doping Agency against Pakistan's decision to overturn bans on Akhtar and fellow paceman Mohammad Asif.
A tribunal in November banned Akhtar for two years and Asif for one year after they tested positive for the banned steroid nandrolone. They had to fly home from the Champions Trophy in India.
An appeals committee on December 5 upheld the fast bowlers' appeals against the punishment, saying they had not knowingly taken the substance and that they had not been properly educated about doping matters.