NEW YORK - Top officials at the NYPD say it's time to take action against subway sex offenders.

"We have individuals that literally since the 1980s have been committing sexual offenses on the train," said NYPD Chief of Detectives Dermot Shea.

The police department has the backing of Governor Andrew Cuomo, who said this week that he wants legislation introduced to ban anyone from the system with at least two convictions for sexual crimes in the subway. He says the length of the ban would have to be worked out, but wants something longer than just a couple of months.

"The precedent is set. We have sexual predators who get locked up and get released and then we say, common sense, we don't want them locating near a school, near an area they have in the past targeted victims. You have people who target victims in the subways," Cuomo said.

The NYPD says it has the power to kick people out of the system only when they're spotted doing something wrong. That means when officers notice a repeat sex offender, they can't do anything until a crime is committed. 

"We now have to follow them sometimes for hours and hours until they pick out their next victim. And this is the most heartbreaking part for our officers. We now have to wait until they victimize that victim so we can move on them and make another arrest," said NYPD Chief of Transit Edward Delatorre.

NYPD statistics show there were 865 sex offenses committed in the system last year, down from a little more than a thousand in 2017. But the NYPD says the numbers are still greater than several years ago.

"This like many other crimes is probably one that is seriously underreported. The fact that we've created a special victims unit specifically - think about it - to deal with crimes of a sexual nature on the subway speaks to the volumes," Shea said.

Mayor Bill de Blasio also seems to be on board with the plan.

Speaking to reporters Wednesday, the mayor said he would support legislation but it would have to come from Albany.

City Councilman Chris Deutsch has proposed a lifetime subway ban as a way to reduce sex crimes.

State Senator Diane Savino has propsed harsher penalties for subway sex crimes, including up to seven years in jail.

The governor's office says it is now exploring how to legislate and especially enforce a ban.