NSW Farmers Grains Committee Chair Justin Everitt said there needed to be a coordinated approach by governments to ensure the bountiful season wasn't wasted.

"This is the second year now that we've had fields chock full of crops and state borders getting in the way of harvest," Mr Everitt said in a statement on Monday.

"We're not talking about bringing all of Sydney to country Victoria or outback Queensland, this is a relatively small number of regional workers who need to go back and forth across the border to get these crops in on time," he said.

"It's time the politicians put their differences aside and put in place some common-sense arrangements or we'll see a man-made disaster unfold across the industry."

Growers in northern NSW say COVID-19 testing sites either aren't in convenient areas or aren't open at appropriate times.

They say harvesting is a 24/7 process, but some testing centres are open from 9am to 3pm.

The need to line up for testing every few days was also putting workers off crossing the border for work as well as inconsistent rules at the borders, Mr Everitt said.

"The trucks will be bumper to bumper this harvest, and any delays will be very costly to everyone involved."

Australian Associated Press