Cash handouts from the federal government's stimulus packages have been likened to a madman at a pub handing out free beer.

Parents, carers and farmers will start receiving bonus payments of up to $950 from Wednesday as part of a $42 billion fiscal stimulus package.

In December, pensioners and low-income families were on the receiving end of cash payments from a $10.4 billion package.

"It's like a madman giving you free beers at a pub - you'll drink them but you won't respect him," Nationals Senate leader Barnaby Joyce told reporters.

Australian Greens leader Bob Brown said the latest stimulus package could take longer to make an impact on the economy than the government had planned.

"The jury's out on that, but the opposition viewpoint that it won't stimulate the economy is clearly wrong," he said.

Families receiving Tax Benefit A will get a $950 back-to-school bonus for each child aged between four and 18.

Recipients of the carer payment or disability support pension, aged less than 19-years-old on February 3, 2009, will also receive $950.

Eligible drought-affected farmers will receive $950 hardship payments from March 24, the same time a $950 one-off training and learning bonus and education entry payment is paid to eligible students.

The one-off bonus of up to $900 for taxpayers, earning less than $100,000, will flow from April.