BHP Billiton said on Friday it expected to lodge a motion within the next few days to challenge a lawsuit filed by Potash to fend off the miner's $39 billion hostile takeover bid.
BHP said its lawyers were finalising details of the dismissal motion which could be filed as early as Friday.
"Sometime in the next few days is right," a BHP spokeswoman said when asked about the timing.
Potash filed a lawsuit in the U.S. District Court in Chicago last week, alleging that BHP misrepresented material facts related to its bid for the world's largest producer of potash.
BHP has said previously it planned to "vigorously" contest the lawsuit.
Potash has rejected BHP's bid and said it has been approached by other parties that are interested in tabling alternative proposals.
Sinochem, China's top chemicals firm, is working hard to come up with a challenge to BHP's <BLT.L> bid for Potash, sources told Reuters this week, although there are reports it is struggling to find a partner.
State-owned Sinochem has a team of around 20 working overtime to come up with options to stall BHP's bid, and was looking to make a decision soon, sources close to the Chinese firm said.
Potash shares last traded at $144.04, 10.8 percent above BHP's offer of $130, indicating investors were expecting a higher offer.