Hanoi Taxi Association Chairman, Do Quoc Binh, said the fares will be slashed by about VND300 (a little more than one US cent) per kilometre, and it will take some 10 days for the companies to complete procedures for the cut.
He explained to Dau tu (Vietnam Investment Review) that in order to cut fares, taxi firms will have to register with the authorities, reset meters, reprint price lists and notify their customers about the change.
He calculated that these changes would cost about VND500,000 (over US$22.2) per vehicle, and a firm operating 200 cars would have to pay VND100 million for such a one-time adjustment.
Hanoi Transportation Association Bui Danh Lien said the association has set specific price levels at which transport enterprises are to adjust their charges, to facilitate the response in transport charges to petrol price fluctuations.
Companies will have to reduce charges if gasoline prices fell to around VND15,000 (67 cents) per litre, and diesel prices fell to around VND10,000 (44 cents) per litre.
On February 18, the retail price of petrol was cut by VND961 to VND13,752 (61 cents) per litre. The price of E5 RON 92 biofuel also dropped by 942 VND to 13,321 VND per litre.
However, Lien said continuous fluctuations in petrol prices and complicated administrative procedures still make it hard for transport charges to be adjusted in a timely manner.
The association has asked the municipal taxation department to permit transport companies to overprint their tickets with new prices, for a quicker and less costly adjustment.
It has also proposed allowing taxi firms to list the new prices on an easily seen external part of the cars, while waiting for permission from the authorities to reset their meters.
HCM City Department of Finance official, Nguyen Mau Phuong Quynh, said that this agency has already asked local automobile transport enterprises to register new rates in light of recent fuel price declines earlier this month.
She told the Voice of Vietnam that, as of February 18, 16 out of 49 fixed-route passenger transport firms in HCM City registered rate cuts of 3-5%. Three out of 14 taxi firms in Hanoi offered rate cuts of 1.2-2.4%.
Quynh said that local authorities have asked companies to register their fares again with February 23 being the deadline, after the latest petrol price cut.
It was estimated that route transport companies whose vehicles use diesel would have to reduce rates by 4.8%, and those using gasoline would have to slash rates by 4.2%, she added.
February 18's cut was the fourth consecutive reduction in domestic petrol prices this year, and the ninth since October 19, 2015.
The last price revision was on February 3, when the price of petrol fell by VND729.