SINGAPORE - The recent spate of rail disruptions have "really upset" Transport Minister Lui Tuck Yew who said they undermined confidence in the transport network and the progress made to make the train networks here more reliable.

He said the recent breakdowns, including Monday's at Bukit Panjang LRT that lasted almost 24 hours because of an electrical fire, show the range of problems rail operators and the Land Transport Authority (LTA) face, adding that there is still much room for improvement.

"While I can accept the occasional breakdown or even a more severe disruption if it occurs very rarely, I am really upset with the current situation in the last few weeks," Mr Lui told Parliament on Wednesday.

"The incidents have inconvenienced too many commuters, disrupted their routines and schedules, and once again, undermined confidence in the transport network and the progress we had made."

The latest disruptions come against a trend of general improvement in train reliability, said Mr Lui. Prior to this, public perception of the public transport system was shown to be improving.

According to the annual Public Transport Customer Satisfaction Survey conducted by UniSIM, Singaporeans' overall satisfaction with public transport had risen to 91.3% in 2014, compared to 88.5% the year before.

Satisfaction with rail had improved by about four percentage points, reversing a four-year decline, while satisfaction levels with bus services had risen for a second consecutive year. The survey was conducted in October last year.

"I think it reflected the fact that commuters were starting to feel the effect of the improvements and investments that we have made in our trains and buses over the last few years," he said.

He acknowledged that the recent breakdowns, however, did rail operators no favours.

"The recent spate of disruptions, coming against a trend of general improvement in train reliability, really pains me," said Mr Lui.