BHP Billiton has brought in more banks to help it find the $70 billion it needs to fund its planned takeover of Rio Tinto, Britain's Sunday Times newspaper reported.

Citing no sources, the paper said BHP has tapped Barclays, UBS, Goldman Sachs, HSBC, BNP Paribas and Santander to work alongside original banker Citigroup on the funding.

Merrill Lynch, originally the other provider of finance alongside Citi, will remain as broker to BHP but will not provide any money, the paper said.

The new financing arrangements, which come as a global credit crunch makes raising money more difficult, will give BHP the flexibility to execute a $30 billion share buyback proposed as part of the deal, or add cash to the current around $130 billion all-share offer, the paper said.

BHP, the world's biggest miner, must make a formal offer by February 6 or leave Rio alone for at least six months under a deadline imposed by the UK Takeover Panel.

Rio shares jumped 4.9 percent in London on Friday on talk that BHP was set to improve its offer to 3.58 of its shares plus A$16.50 cash for Rio from a three-for-one all share offer, which was worth $140 billion when revealed last November .

Separately on Sunday, Rio Chief Executive Tom Albanese left the door open to a sweetened takeover offer from BHP Billiton, but said Rio would be happy to grow on its own if BHP walked away.

It's again all about value. If the value's not there, it's not there. If it is there, it is there. But I wouldn't want to speculate on anything specifically, Albanese told Sky Television.

United kingdom BNP Paribas Citigroup