In a special four-day operation last week, it snared 41 of these black sheep who tar the image of the country's 23,000 taxis plying the roads.

The blitz, from Oct 24 to 27, targeted popular or busy spots like Boat Quay, Clarke Quay and Orchard Towers.

Twenty-two were caught for touting, 11 for refusing to pick up passengers, and eight for overcharging.

All the cases are being investigated and appropriate action will be taken, the LTA said in a statement on Wednesday.

It added that it will step up enforcement operations on weekdays and weekends.

Between January and September this year, LTA penalised 287 errant taxi drivers - up from last year's 202.

The LTA's blitz followed mounting media reports and readers' complaints about the increasing brazenness of a minority of cabbies who pick and choose fares, refuse to use the meter, or overcharge passengers, usually tourists.

Concerns have also been raised that such drivers will tarnish Singapore's image as a top-class tourist destination.

Such errant behaviour by taxi drivers has been a hot topic with an irate public in recent months. The Straits Times and its online portals received more than 100 complaint letters recently.

A Sunday Times report on Oct 14 highlighted the extent of the problem at the busy 'hotspots'.

Project officer David Segar, who was interviewed then, said: 'It's frustrating when cabs refuse to pick up locals, but only stop for tourists who pay ridiculous prices.'

Student John Tan, 24, said a cabby quoted him $50 for the ride from Orchard Road to Bedok at 10.30pm on Tuesday night.

'I told him I am Singaporean, but he had the cheek to say he would waive the midnight surcharge, at 10.30pm!'

Read the full report in Thursday's edition of The Straits Times.