Increasing costs of production are beginning to bite into the operations of manufacturers of consumer goods. For many, retail prices are becoming their biggest concern.   Siam Cement Plc, the country’s leading cement manufacturer, yesterday announced its first increase in cement prices for two years, saying its production costs have risen by 50 per cent since 2004.   Siam Cement’s president Kan Trakulhoon said the group had been affected by increasing energy costs, but it stayed its price increases to avoid burdening its retail customers.  
 
"With continuous increases in oil prices over the first quarter of this year, we have made a request to the Commerce Ministry to adjust our retail price on some product items, such as cement," Kan said.  
 
"The energy cost in our cement business has risen by 50 per cent over the past two years and accounts for between 10 per cent and 20 per cent of the total cost of sales. Forced by the declining domestic demand for cement and an oversupply of cement on the market, we decided we can raise our retail price a little," he said to local newspaper, The Nation.