Talib Ait Ahmed, a cannery worker from the southern coast city of Agadir, said he was protesting for a better life for workers in the face of the rising food prices and widespread unemployment.
Ait Ahmed acknowledged that the government faces constraints, but complained that the prime minister wasn't doing anything to improve economic mobility and expand the small middle class.
"He's not reacting. He sees the problem but hasn't taken it in hand yet," Ait Ahmed said.
Despite some reforms following the 2011 Arab Spring demonstrations, true power in Morocco lies with the monarchy and those close to it. Benkirane has repeatedly blamed "remnants" of the previous government in the bureaucracy and administration for blocking his reform efforts.
A poll published Friday by the daily L'Economiste gave Benkirane a 64 percent approval rating after just over a year in office. The paper noted it was a comfortable margin, but a 22 point drop from his 88 percent rating last year.
Associated Press reporter Smail Bellaoualli contributed to this report.