More interested suitors are circling around Potash Corporation of Saskatchewan and may try to top BHP Billiton's takeover offer, media reports say.

The Economic Times of India reported Monday that China's Sinochem had approached the Indian state-owned iron ore miner, NMDC, about making a joint bid for the Canadian fertilizer company.PotashCorp NYSE three-month trading chart. (CBC)

NMDC's chair quickly denied this, telling Reuters, "There is no such proposal."

In Britain, the Sunday Times reported the Ontario Teachers Pension Plan had approached an investment fund in Singapore about launching a bid, possibly with the help of Teck Resources.

Several British papers also reported that PotashCorp was thinking of some defensive measures that could include breaking itself up.

None of the companies commented.

BHP Billiton launched a hostile $38.5-billion US bid for PotashCorp in August. The offer would give PotashCorp shareholders $130 US for each PotashCorp share they own.

PotashCorp has officially rejected the takeover offer, saying it undervalues the company. PotashCorp shares have traded well above the $130 US level since the bid was made public — a sign the market believes BHP will either have to raise its offer or that a richer offer will emerge.

PotashCorp stock closed Monday with a gain of $1.90 at $147.70 US on the NYSE.

With files from The Canadian Press