Speaking at the Hants & Dorset dinner in Bournemouth on Friday, Mr Plews said no-one had a problem with prices going up but he was concerned at how quickly they were rising.
“Traders aren’t being loyal to their customers,” he said.
Speaking to TTJ later, Mr Plews said everyone could make money from a rising market but traders needed to give their customers time to pass on the price rises.
“At the moment the customer is being squeezed in terms of margins,” he said. “There is a moral obligation for suppliers to lead the market but lead it in a way that allows customers to follow.”
He pointed to North America where, despite a tight supply of timber, losses were being made.
Mr Plews also warned that if timber prices were pushed too high it would make other products more competitive.
“Be careful,” he said. “No-one has a problem with prices going up but do it slowly and carefully.”