TORONTO (Reuters) - China's Sinochem Corp has hired banks to advise it how to foil BHP Billiton's $39 billion bid for Potash Corp, two sources with direct knowledge of the matter told Reuters.

The state-owned chemicals group had hired Deutsche Bank and Citigroup for the purpose, the sources said after BHP extended its offer for Potash, the world's largest fertilizer group, by a month to November 18 to provide Canada's competition regulator with more information.
""Sinochem has been given an extra window of a month within which to decide whether and how they are going to bid,"" said London-based analyst Dominic O'Kane at Liberum Capital.
""Clearly a large component of that will be determining whether they will get regulatory approval in Canada. If they think they will get regulatory approval, they will bid. If they don't, they won't,"" he added.
Interest in Potash is being fueled by an expected surge in fertilizer demand from China, India and other emerging economies due to rising food consumption.
Given the political obstacles in Canada, any Chinese bid would have to be part of a larger consortium to have a chance of succeeding, analysts said.
One obstacle facing officials in Beijing is that China, as a top consumer of potash, would want to keep prices low for the vital crop nutrient, whereas most consortium members would want to maximize returns with higher prices.