Prime Minister Scott Morrison announced a further $100 million of extra assistance measures to help farmers and communities as the crippling dry continues to bite.

Asked on Sky News Speers program on Sunday whether such support jeopardised Australia's free-trade obligations, Senator McKenize said: "No, it doesn't at all."

"This is not a US-style farm bill subsidy program at all," the deputy Nationals leader said.

"As an exporter of 70 per cent of what we produce, we don't want to be doing anything here at home that puts at risk our ability to trade."

The latest assistance program included a $51.5 million overhaul to the Farm Household Allowance for producers doing it tough.

The eligibility criteria will be extended and simplified, with the government estimating less than 7000 of the 24,000 eligible households are currently accessing it.

Mr Morrison assured proud farmers who may be reluctant to claim financial help that such payments were not welfare.

Senator McKenzie said while Centrelink still handles the allowance, there has been a raft of changes in the way the agency interacts with the farming communities and making sure there is a much more farmer focused, client case-management approach.

"So they are not having to explain their circumstances to 20 different people, they are not having to sit on the phone for hours on end," the minister said.

She said Centrelink would not issue a debt notice if farmers under estimated their earnings, although there would now be random and targeted audits rather regular reporting.

"If you are eligible for one dollar of Farm Household Alliance, you will be paid the maximum rate," she said.

Australian Associated Press