Metro will open ticket barriers at city stations to avoid the peak-hour commuter crush sparked by the roll-out of myki.

The move, designed to ease potentially dangerous crowds, could result in some myki users being overcharged - and might entice others to evade fares.

Commuters took to Twitter in frustration at long queues at the Flagstaff station barriers this week. Credit:Daniel Bowen

‘‘Today we resolved to do this every morning and afternoon during peak hour,’’ Metro spokesman Daniel Hoare said.

He said the rollover to the myki ticketing system had caused congestion at train stations, with passengers struggling to use the new "smart cards".