Congress should slash at least $100 billion in costs from the U.S. farm bill – three or four times more than cuts currently proposed – and resist calls for a hurry-up vote this week, a dozen anti-deficit and environmental groups said on Monday.

At a news conference, they said the $5 billion-a-year “direct payment” subsidy to farmers should be eliminated as part of temporary legislation that would bridge the gap to a new five-year law in 2013.

That would give lawmakers time for a clear-eyed overhaul of farm policy, they said.

Milk prices at the grocery store could double next month under an outmoded statute that took effect with expiration of the 2008 farm law on Sept. 30. It would be the first major impact to be felt from the failure to pass a new farm law.

Agricultural leaders in Congress now hope to attach the farm bill to a deficit reduction package that is needed by year’s end to avoid automatic tax increases and spending cuts in January. They say the $23 billion to $36 billion in proposed savings in the farm bill could help reduce the federal debt.