"We are talking about four billion dollars," Tymoshenko told a news conference after meeting EU officials in Luxembourg.
"We are today working on the idea of borrowing these credit resources in European banks and the European side is favouring this as well as the Russian side."
She said she believed Naftogaz was "going to be able to have the credit resources necessary in order to do this operation".
Tymoshenko and President Viktor Yushchenko have been at odds on how to finance state energy company Naftogaz, one of a long list of issues pitting the two former allies from the pro-Western 'Orange Revolution' against each other.
Yushchenko accuses Tymoshenko's government of pursuing policies that will bankrupt Naftogaz, including the use of credits to purchase imports of Russian gas. He said company credits to be repaid totalled 74 billion hryvnias ($9.7 billion) compared to 56 billion at the start of the year.
Tymoshenko says she is making every effort to make Naftogaz a viable company and has promised prompt payment for supplies to prevent any repetition of a January standoff with Russian giant Gazprom, which cut off supplies to Europe for more than two weeks.
In her comments to reporters, Tymoshenko said storage and continuous supplies of gas were important issues for all sides in the trade - Russia, Ukraine and the EU. She said she had told EU Commission President José Manuel Barroso that Ukraine had already started storing gas in April.
"We have always paid for the gas that we have received and are partners that can be counted on," she said.
"I would like to say that everything is going to happen in a very successful fashion and there is no reason to expect any difficulties for gas transit to EU countries for Russian natural gas."
(EurActiv with Reuters.)
