The White House issued a veto threat against a multibillion-dollar farm bill, complicating passage of the legislation as House members scrambled Wednesday to find $4 billion to pay for food stamps and other nutrition programs.

Agriculture Secretary Mike Johanns said the House bill, which extends government agriculture and nutrition programs, doesn't do enough to reduce subsidies to growers.

"We believe the bill put forth by the committee misses a major opportunity," he told reporters.

Meanwhile, House Republican leader John Boehner, R-Ohio, said Republicans would fight a provision that would tax overseas businesses in order to pay for the nutrition programs.

The chamber is expected to begin consideration of the five-year farm bill Thursday. House Speaker Nancy Pelosi, D-Calif., has backed the legislation but faced criticism from groups who say it doesn't go far enough to trim government programs.

The bill, approved unanimously by the House Agriculture Committee last week, contains modest attempts at reform. It would ban federal subsidies to farmers with incomes averaging more than $1 million a year and stop farmers from collecting payments for multiple farm businesses. The Senate is due to begin its consideration of the legislation in September.

Pelosi called the bill a "critical first step for reform."

But Johanns said the millionaires proposal would only affect about 7,000 farmers, noting that the administration has suggested limiting subsidies for those with incomes of more than $200,000. That would affect 38,000 farmers, Johanns said.

"There is a point at which people graduate from receiving government cash subsidies," Johanns said.

House Agriculture Chairman Collin Peterson, D-Minn., swiftly criticized the administration.

"Today, the Bush Administration failed rural America and all Americans," he said. "This farm bill is supported by a broad spectrum of agriculture, conservation, nutrition and renewable energy advocates."

Johanns also criticized the proposal by Rep. Lloyd Doggett, D-Texas, to pay for $4 billion in nutrition and food stamp programs by taxing overseas businesses that have subsidiaries in the United States. Doggett is on the Ways and Means Committee, which is charged with finding the nutrition money before debate begins Thursday.

"I find it unacceptable to raise taxes to pay for a farm bill that contains virtually no reform," Johanns said.

Boehner agreed.

"You can't increase the security of American farmers by destroying millions of American jobs and endangering the economic freedom and security of millions of our working families," Boehner said in a statement.

A spokeswoman for Virginia Rep. Bob Goodlatte, the top Republican on the agriculture panel, said he is "very concerned" about the Doggett proposal. He has otherwise supported the legislation.

Republican officials said their members — even those from rural states that would benefit greatly from the farm bill — were loath to support what they viewed as a massive business tax increase that could invite retaliation against U.S. firms that establish operations abroad.

"It is bad policy and bad politics," said Rep. Jim McCrery of Louisiana, the top Republican on the Ways and Means Committee. "Democrats are trying to sneak a far-reaching and potentially destructive proposal through the House without proper consideration. Any fair-minded person who cares about the U.S. economy will oppose this bill."

With many Democrats already uneasy about the agriculture measure, which leaves in place and in some cases increases subsidies for major crops, Republican defections could spell defeat for the bill.

Without the additional $4 billion for nutrition programs, however, Democrats would lose substantial support for the measure among lawmakers from urban districts that draw heavily on those programs.

A statement of policy issued by the White House said the House bill "moves backward" and could compromise international trade negotiations.

The administration also expressed concern that the bill includes Davis-Bacon Act provisions on paying prevailing wages on ethanol plant construction projects. The requirement typically gives an advantage to unionized companies bidding for federal contracts.

Johanns praised a proposed amendment by Reps. Ron Kind, D-Wis., Jeff Flake, R-Ariz., and others to further cut back on subsidies and steer more money toward conservation, aid for specialty crops like fruits and vegetables, and nutrition and rural development programs.

But that effort has divided Democrats and caused concern among farm-state lawmakers who argue it would devastate agricultural programs and cost the party its newly won majority.