The more than 9,000 city employees represented by AFSCME District Council 33 have been working without a contract since July.
Chopper 6 was over City Hall Wednesday evening as a massive group of workers marched around Center City.
Mayor Cherelle Parker wants the union to agree to a short-term deal.
"It's not our place to discuss the union's tactics or strategies," said the Parker administration in a statement Wednesday. "We remain confident in what we've negotiated throughout this year with every other union representing our municipal workers, and we believe we will be able to find an amicable resolution with District Council 33's leadership and membership as well."
The union is asking for a longer agreement, pay raises, and pension revisions.
AFSCME represents blue-collar employees such as sanitation workers.