TRANSPORT Minister Troy Buswell's intervention halved the waiting time for his son's practical driving assessment in October 2012, a Legislative Council committee meeting heard today.

The Parliamentary hearing was told that the normal waiting time for a driving test would've been 6-8 weeks in 2012 but Mr Buswell's son was able to do the test in less than four weeks after his office intervened.

The hearing was told that in September 2012 an officer from Mr Buswell's ministerial office contacted the managing director of Transport Services, Nina Lynne, and requested that Mr Buswell's son be tested on the last day of school holidays, October 12.

There was no one available in Busselton to do the test that day but a regional transport officer was then arranged to do the test - the only one on October 12.

The hearing was told that Mr Buswell had tried to go through the normal channels and book a test for his son by telephone but had become frustrated when he was unable to - so he instructed his ministerial staff to approach Ms Lynne for help on his behalf.

Ms Lynne then contacted the general manager of regional services, Peter Olarenshaw, who made the special booking for Mr Buswell's son.

The hearing heard that under normal circumstances complaints of this nature would normally be dealt with by a complaints officer within the department.

The latest controversy to hit Mr Buswell was revealed by The Sunday Times on the weekend.

Opposition transport spokesperson Ken Travers questioned transport officials about the events and told the media today Mr Buswell had done the wrong thing.

"It is clear the Minister requested that the test be conducted on a specific date and that the department put in place special arrangements for that to occur," he said.

"It was on a date when there was not an appointment available to the Minister.

"This is completely contrary to what the Minister said on Monday."

Premier Colin Barnett this week defended Mr Buswell, saying he was merely trying to be a father and help his son.