About 75 per cent of the 400 Chinese national bus drivers in SMRT are now union members, said Labour Chief Lim Swee Say in Parliament Monday afternoon.

Responding to questions from MPs, Mr Lim noted that prior to a strike last November, less than 5 per cent of SMRT's PRC drivers were union members.

Since then, about three-quarters of the transport operator's drivers have signed up.

Over at SBS Transit, more than 90 per cent of their 600 Chinese national drivers are union members, Mr Lim said.