Mr Sinclair said the same situation was being repeated at test centres across the UK.
“Because of the national backlog, cancellation apps have turned booking a test into a finger on the buzzer situation, where whoever grabs the slot gets it first, regardless of location,” he said.
“Tests here are often taken by people travelling long distances, many of whom aren’t familiar with the area.”
“Local instructors aren’t allowing this to happen. Myself and my colleagues simply can’t and won’t take candidates to test if they’re unprepared or unfamiliar with the area.”
Mr Sinclair said he sympathised with people being in a desperate situation because of the backlog.
He said that when a candidate fails a driving tests they often have to wait months for another opportunity, which can have an affect on employment opportunities.
“For some pupils, the increased waiting times can increase anxiety, cause loss of confidence and frustration,” Mr Sinclair said – as well as the financial pressures.
According to the NAO report, most driving test centres in Scotland still have waiting times of more than five months despite efforts to reduce the backlog.
It found that most of Scotland’s 24 permanent centres had waits of between 19 and 24 weeks.
Just two Scottish centres – Dumfries and Ayr – had average waits of six weeks and under.