CALTEX lowered its prices for petrol and diesel overnight, a welcome move for Hongkong motorists which the company says could soon be followed by a further cuts. Caltex, which owns about one third of Hongkong's filling stations, said yesterday that the price for petrol would fall this morning by five cents per litre for leaded and unleaded petrol to $8.25 and $7.91. The prices are still higher than before the last rises in April, when oil companies lifted petrol prices by 16 cents to $8.30 for leaded and $7.96 for unleaded. Caltex general manager and director Ralph Perry said that although price cuts for petrol were unusual in summer, petrol prices might fall again soon - but this was not as likely as another drop in diesel prices. Prices for diesel will fall this morning by seven cents, taking the cost per litre of ordinary diesel to $5.27, light diesel to $2.86 and boiler diesel to $2.66. Shell, which owns the most filling stations, with about 35 per cent of the retail market, said last night that it would evaluate Caltex's price cuts overnight before announcing whether or not to match them today. But Shell's retail and advertising manager, Norman King, agreed with Mr Perry that further price drops for diesel were possible. ''They have been falling for a while and then they rally for a day or so and then drop back again, so if I were a betting man I would also expect diesel prices to fall,'' Mr King said. Mr Perry said the recent failure of the Organisation of Petroleum Exporting Countries to agree on a production accord, and the expectation that Iraqi crude oil might flow back onto the world market, were pushing the price of oil down. Any drop in fuel prices is important in terms of putting downward pressure on local inflation.