Dozens of mask-less commuters were spotted breezing by Port Authority cops on the first day of the agency’s $50 fine for mask non-compliance Monday.

Between 1 p.m. and 3 p.m. on Monday, a Post reporter counted 42 different people entered the Port Authority Bus Terminal’s south entrance without masks on.

Port Authority cops stationed at the entrance declined to comment — or take any enforcement actions against most violators.

The transit agency instituted the $50 fine for anyone who refuses to mask-up in any of its facilities, including the bus terminal and all three of the New York region’s major airports.

New York Gov. Andrew Cuomo instituted his own fine on MTA transit properties in September.

So far, actual fines on MTA systems have been fairly limited — officials say the financial penalty is merely a “tool” meant to encourage more compliance.

A Port Authority spokeswoman echoed the MTA’s line.

“We’re seeing over 95 percent voluntary compliance with mask-wearing at our facilities, including at the Midtown Bus Terminal,” spokeswoman Lindsay Kryzak said in a statement.