STORED value cards could be used instead of cash to pay taxi fares if the results of tests conducted on taxi card-meter machines are approved by the Government. But while taxi drivers were sceptical about the stored value cards, many agreed they would be more convenient for passengers who do not carry large amounts of cash. The machines, which have already been installed in some taxis for a test run, accept cards similar to those used in the Mass Transit Railway (MTR). Customers would be able to buy the cards from taxi stands and the amount charged for the journey would be deducted accordingly. Mr Ng Kwok-hung, spokesman for the Hongkong and Kowloon Taxi and Lorry Owners Association, said his organisation had no immediate plans to implement such a scheme. ''Unless there is a new policy for the rental of taxis by drivers, the card scheme will not work,'' Mr Ng said. Taxi drivers who rent the vehicles pay a daily rate from their daily takings. The new scheme will mean taxi drivers will receive their wages after amounts charged from the cards are calculated at the end of the month. ''If the scheme was to be used, meaning there would be no cash involved, the drivers would have to fork out money for their daily livelihood and then another sum for the monthly rental,'' Mr Ng said. One taxi owner, who had a German-made machine installed in his vehicle, said it was being tested. The owner said a stored value card system would be helpful for passengers wanting to go to Shenzhen or places in Guangdong province in future. Reports in 1988 indicated that a China-owned concern, Chu Kong Shipping was interested in setting up a taxi fleet to run between Hongkong and Shenzhen. But Mr Ng estimated it might take two years for the scheme to be introduced. ''And time is also needed for the drivers and customers to adapt to the scheme.''