A change in vendors used by the U.S. Department of Agriculture to supply badly needed food to local hunger relief organizations has severely cut back on its deliveries to the state, members of the Massachusetts congressional delegation said Tuesday.

“You can't get enough food out there right now,” said Sasha Purpura, of the Cambridge-based Food for Free Committee. “And that's why these boxes were so important, because they allowed for safe distribution of food in organizations that are under-resourced and don't have, you know, huge facilities and resources."

The organization has seen its USDA deliveries cut than 2,000 boxes a week down to about 500, Purpura said.

The USDA has not explained why this cutback happened, but congressional representatives said the timing is terrible as demand for food in Massachusetts during the pandemic has shot up more than 50%.

“American families must always have access to basic necessities, but never more so than during this pandemic,” said Massachusetts Democrats Rep. James McGovern, Sen. Edward Markey and Rep. Ayanna Pressley in a statement. “To ensure their needs are being met and that the program is effective, USDA must engage in effective oversight.”

The Farmers to Families Food Box Program began last spring under federal coronavirus relief legislation that directed the USDA to purchase and distribute agricultural products meant for schools, food banks and families experiencing hunger.

The Greater Boston Food Bank said today that the box program has been cumbersome to navigate because the vendors and terms have changed four times since it started. But spokeswoman Catherine Drennan said the food supply filled a gap for both the food bank and partner organizations.

A reduction in spending by the U.S. Department of Agriculture has severely cut back on badly needed food deliveries to local hunger relief organizations, members of the Massachusetts congressional delegation said Tuesday.

“The carpet was kind of pulled out from under a lot of organizations because they were relying on this program,” she said. “A lot of organizations outside of the Greater Boston Food Bank Network are no longer now receiving (the) product, so that's the big issue. There is all of the sudden a huge gap within the food network.”

The USDA told GBH News that funding for this latest round of food assistance is about half what the agency spent in previous cycles of the since coronavirus relief legislation created the Farmers to Families Food Box Program.

The state’s congressional delegation said it is trying to get answers from the USDA while some food pantries are now scrambling to make up for the shortfall.

Meanwhile, the Food for Free Committee is seeking more cash donations so it can buy food while also teaming up with an organization that gleans unused food from farms, food service companies and grocers.

This story has been updated to include a response from the U.S. Department of Agriculture.