Prices of chemical fertilisers were already high since most of the raw materials were imported, Mr Yanyong said.
Chemical fertiliser prices in May 2008 ranged from 27,000 to 28,000 baht per tonne, but had recently dropped to 14,000 to 15,000 baht a tonne. The price of a 50 kilogramme bag of chemical fertiliser had fallen from 1,300 to 1,500 baht last year to 700 to 800 baht this year.
He said the increase in oil prices did not justify a rise fertiliser prices at the moment.
Palm oil prices had slightly increased due to lower output in the country and higher demand from foreign countries.
Desite the call by vegetable oil traders for an increase in prices, the Internal Trade Department chief said the price of crude palm oil should be between 4.50 and five baht per kilogramme.
He believed this range would allow palm oil farmers to earn good profits, but the palm oil factor would not prompt the government to raise vegetable oil prices.