Global miner BHP Billiton on Sunday played down any chance of raising its $39 billion (25 billion pound) bid for fertiliser maker Potash Corp

, saying it had timed its move to catch out weakened rival bidders.

Chief Financial Officer Alex Vanselow, speaking in an Australian television interview, also said the hostile bid had been timed to ensure more ready access to credit markets.

The opportunity in Potash is that we are now in a situation that our balance sheet allows us to raise the credit necessary to buy, the valuations match, and basically if you look at the landscape of competitors, they're not in the same position as we are, Vanselow told ABC's Inside Business show.

So you've taken all this into consideration -- you can see this is an opportune time to make a bid.

BHP, the world's biggest miner, unveiled its biggest half-year profit in two years on Wednesday, with just $3.3 billion (2.1 billion pounds) in net debt and gearing at a low 6 percent, putting it in a strong position to raise its offer if necessary.

Potash Corp's shares last traded 14 percent above BHP's offer price, as investors bet that BHP will have to pay more or another bidder will emerge, but Vanselow said there was no need for BHP to raise its offer of $130 (83.68 pounds) a share.

There is only one offer on the table, so why would we compete against ourselves?

Rival miner Rio Tinto is considered unlikely to make a counterbid as it has only just recovered from a mountain of debt it took on for its $38 billion (24 billion pounds) takeover of Alcan three years ago. Rio Tinto has since said that it would only consider smaller acquisitions.

Brazil's Vale , which is building a potash business, has said it is not looking at Potash Corp.

That has stoked speculation that the only potential counterbidders would include a player from China, the world's biggest importer of potash, a key nutrient needed to boost crop yields as food consumption soars.

China's largest fertiliser distributor, Sinofert Holdings Ltd <0297.HK>, said on Thursday it was worried a BHP takeover of Potash Corp would have a big impact on the company but would not say if its parent, Sinochem, was planning a rival offer.

BHP CEO Marius Kloppers is in North America, set to meet with BHP shareholders to discuss the bid and the group's results. He is expected to start wooing Potash Corp shareholders, many of whom are also BHP stakeholders.

A Reuters survey indicated Potash shareholders would accept $162 (104.28 pounds) a share.

Under UK listing rules, the $39 billion (25 billion pounds) offer does not need a BHP shareholder vote as it is worth less than 25 percent of BHP's market value of $188 billion (121 billion pounds) the day before the bid was launched.

But if the bid were sweetened, the 25 percent threshold would apply to BHP's market value on the day before the announcement of the higher offer. Based on BHP's market value on August 27, an increase of just over 10 percent in the bid to $43 billion (27 billion pounds) would be enough to trigger a BHP shareholder vote.

Vanselow said BHP would also look into what happened at Santander , the euro zone's largest bank and an adviser on BHP's bid, after one of the bank's employees was charged by the U.S. Securities and Exchange Commission with insider trading in Potash Corp securities ahead of the bid.

Asked if BHP would hesitate to use Santander again, he said: I think we will investigate what happened, we'll get the feedback from Santander and then we'll decide on that.

(Reporting by Sonali Paul; Editing by Mark Bendeich)