Falling oil prices have been a boon for taxi driver Ng Chin Guan, who has reaped savings every month.

He estimated that he saves between $120 and $150 a month, compared to about 11/2 years ago.

The lower oil prices have made Mr Ng, who drives a taxi for about 60 hours a week, more willing to drive around looking for passengers during non-peak hours.

Diesel from Caltex cost about $1.05 per litre on Jan 14, down from $1.71 per litre on June 26, 2014, data from Petrol Watch showed.

Grade 98 petrol from Caltex before discount was priced at $2.46 per litre on June 26, 2014.

It had dropped to $2.23 per litre as at Jan 14.

Pump petrol prices have not dropped as fast as crude oil prices, mainly because crude oil cost is just one component of the final pump price.

Other factors that influence fuel costs include land, building and distribution costs.

Duties for petrol were raised by the Government during the Budget last year, further adding to costs.

Mr Ng said the slower economy is hurting his monthly takings, which have fallen by about 5 per cent since 2014.

"The economy is not doing well, so people try their best not to take taxis and use public transport (instead)," said Mr Ng, 50.

"Expatriates are also getting retrenched and not coming; a lot of property agents are also taking taxis less frequently. These will all impact us."

Competition has also been heating up from private car hire services such as Uber and GrabCar.

"You just have to grit your teeth and hope for the best. If you're lucky enough, you can make up the shortfall," Mr Ng said.

Pump prices have fallen from mid-2014 levels, lowering fuel costs for taxi drivers and regular car owners.