Things have gone from bad to worse for Auckland rail commuters with cancellations becoming the norm in recent weeks.

20 cancelled trains disrupted travel plans for thousands yesterday.

Nine were cancelled on Wednesday and 15 on Tuesday.

Technical issues are hampering both the old diesel trains, and the new electric trains.

In a statement, Auckland transport is blaming the old diesel trains for the problems and is trying to speed up the roll out of the new electric trains, but it's understood some of the cancellations are being caused by bugs in the multi-million dollar fleet.