The MetroCard swipe will be around about three years longer than expected before riders can start "tapping" their way into the system, MTA officials said Tuesday.

Backing off a schedule officials had called "aggressive," the new system will start to be phased in for riders in 2020, instead of late 2016 as the MTA anticipated in May. The last swipe could be in 2022, when the MetroCard is expected to officially go the way of the token, as the current system gets increasingly expensive to maintain. The MTA is making sure that the MetroCard system can stay in good shape until 2023.

The experience of other mass transit systems' efforts to update their fare payment technology had the MTA reassessing its timetable.

"There's one example of where stepping a little bit too far and a little bit too aggressively on the technology front presented a problem," MTA chief Tom Prendergast said at a board meeting, adding that "you want to get it right the first time."

The MTA wants to take advantage of the devices most New Yorkers carry with them already by having turnstiles and buses fitted with electronic readers.

"This is more like a chip-based product: a phone, or a contactless credit, debit card or a prepaid card," said Michael DeVitto, an MTA official.

Different options are under consideration for those people still armed with a flip phone or unable to get a bank card, such as an MTA card that the agency makes itself, according to DeVitto.

The MTA has budgeted $450 million since 2010 to develop the new fare payment system, though an independent engineer said that amount could fall short once full costs are tallied. The MTA anticipates awarding a contract in 2016 to start the design, development and installation process. Buses will be ready for the new fare payment system first in early 2020, with subways getting the technology by the end of summer that year, according to the MTA's timeline.