Fewer than one-third of 21,000 daily passengers predicted for south-east Queensland's newest train line are actually using the line two years after it opened, TransLink statistics show.

The main reasons for the poor passenger demand were no express services in peak hour, poor connections with buses and a slow service with trains stopping "all stations", a transport lobby group said.

South-east Queensland’s Petrie to Kippa-Ring train line (Redcliffe Peninsula line) opened in October 2016, amid controversy over train drivers and services.

Poor bus links and no peak hour express services have left the Kippa-Ring to Petrie rail line with only one-third the projected passengers.

In that first month, there were only 4709 daily passengers.