"If the dollar stabilises and China's banking system hits trouble, the commodity market could be in trouble," said Michael Howell, managing director at UK-based Crossborder Capital.
He told a conference organised by Worldwide Business Research in London that a large part of commodity price gains in recent years were due to the generally weaker dollar rather than strong economic growth.
"We feel weaker US currency makes dollar-denominated commodities cheaper and more attractive to investors holding other currencies," Howell said.
"We are in a real asset bubble and at some stage that bubble will burst, prices may come down rather significantly. The argument for a supercycle is not that strong," the investment advisor pointed out.
Howell compared the recent commodity bull run to Japanese stocks in the 1990s and more recently the dotcom bubble in 2000.
"If you look at commodity price gains over the long term, what you see is that the biggest gains occur when the dollar is weak ... One of the things people will throw back at me is the China effect," he added.