There are more wannabe green outer borough taxi drivers waiting to buy permits than are available, Taxi and Limousine Commissioner Meera Joshi said Monday.

With the city slated to sell a second batch of 6,000 permits mid-August -- more than a year after the program debuted -- 6,300 prequalified drivers were put on a waiting list, according to Joshi.

"There is a small business opportunity here that people think is viable and that's why so many people have signed up to buy in the second wave," Joshi told reporters after a City Council hearing.

Mayor Bill de Blasio, an early critic of the green taxi program launched by his predecessor, Mayor Michael Bloomberg, had slowed its expansion after the initial roll out of 6,000 permits last year. A second round was slated to go out this month, but the TLC decided to hold off on issuing them until August to let the agency reach out to industry stakeholders. Joshi anticipated a third tranche of permits once the second set is completely sold.

"Overall, everybody's accepted that its part of life in New York now," Joshi said.

In its first year, green taxis, limited to the outer boroughs and northern Manhattan, clocked 5.8 million trips for 6.9 million passengers. Northern Manhattan was the busiest area for green taxis at 1.8 million trips, followed by 1.6 million trips in Queens, 1.4 million trips in Brooklyn and 6,000 trips in the Bronx. Car-heavy Staten Island used green taxis the least, with 1,600 trips in a year.

There were, however, enforcement concerns expressed at the Council hearing about preventing the green taxis from entering the main Manhattan business district and stealing fares from yellow taxis. There were 870 summonses issued to green taxi drivers and owners for picking up a fair inside the zone exclusively for yellow cabs. The summons comes with a $500 fine for first-time offenders.

Erhan Tuncel, a driver-owner who is managing director of the League of Mutual Taxi Owners, said issuing more green taxi permits than necessary would encourage illegal street hails. He suggested enlisting the NYPD to catch green taxis picking up Manhattan fairs meant for yellow cabs. "If there is too many of these permits issued and then the drivers are not able to make money within that industry what is the other option for them?" Tuncel said. "The other option for them is to break the law."