Berkshire Hathaway Inc said it voted against Kraft Food Inc's proposal to authorize the issuance of up to 370 million shares to help the food maker buy Cadbury , but could reverse to a yes vote, depending on the final offer's details.

The proposal, if enacted, would give Kraft a blank check allowing it to change its offer for Cadbury, billionaire Warren Buffett's insurance and investment company said on Tuesday.

And we worry very much that, indeed, there will be an additional change from the revision announced this morning, Berkshire added in a statement issued on Tuesday.

Earlier, Kraft sweetened its $16.4 billion offer for Cadbury with a bigger cash portion, while Nestle took itself out of the running for the chocolate maker.

Berkshire said it does not believe any Kraft shareholder should vote yes to the proposal without knowing what they are voting for. However, it said that it would change its own vote from no to yes if, after seeing the final offer Kraft is expected to present later this month, it concludes that the offer does not destroy value for Kraft shareholders.

Berkshire Hathaway believes that it is the largest Kraft shareholder, holding 9.4 percent of the food-maker's shares in its own holdings and those of its pension funds.

The full Berkshire press statement appears at