The wheat producer and chairman of Grain Growers, the peak Australian grain industry body, normally farms 400 hectares of wheat on his property 250 kilometres south-west of Tamworth, in the Warrumbungle shire of north-west NSW.

Mr Eastburn "didn't plant seed this time around because it was too dry at planting time and rain wasn't expected to hit until September".

September's far too late for rain - he'd normally be reaping his crop around then.

???Less than favourable weather has made this year challenging for many grain growers, with winter crop production forecast to fall 41 per cent, going from last year's bumper season of 59.5 million tonnes to 34.8 million tonnes, according to data from the Australian Bureau of Agricultural and Resource Economics.

That's part of the reason the agricultural sector was a stand-out in Wednesday's refresh to the ABS national accounts, with production falling 4.1 per cent and contributing to a hold back of our GDP growth rate to 0.6 per cent in the September quarter, below market expectations of 0.7 per cent.

This is the second consecutive quarterly fall for the agricultural sector, making it the only industry to record overall negative growth in the past 12 months.

"Everything is very tight" this year for Mr Eastburn.

???On top of wheat, he usually grows oats to feed his cattle, but this year he had to bring in hay.

The dry weather has restricted him from buying new fencing and equipment, a familiar tale for weather-affected grain growers across the east and south of Australia.

Peter Woods, director of AvantAgri, said "there will be little to no exports out of NSW and Queensland".

He said we would have to wait until all the harvest was over to see how much damage had been done to Australia's exports.

"Normally you'd know by the end of December but the rain has delayed that to probably the end of February," he said.

"This is unfortunately what happens when we get a drought on the eastern seaboard" and it's only "compounded in southern NSW, Victoria and South Australia with frosts and now rains at harvest".

Mr Eastburn expects national wheat production to fall below average levels partly because this late dumping of rain has downgraded the quality of a lot of grain.

If water gets into the grain, "the head thinks that it has just been planted so it wants to shoot", he said.

"And once it shoots, it's virtually no good to use for baking - it becomes a feed wheat for cattle or sheep or other animals.

"So that means the price goes from $300 a tonne to probably $150 a tonne, depending on how much weather damage there is in it."

Lachstock, an agribusiness consultancy firm, estimates between 1-1.5 million tonnes of wheat has been downgraded.

Lachie Stevens, managing director of Lachstock, said the rain this year has been significant but "we get it from time to time so the market is pretty well adapted to solving the problem".

It's a different story on the other side of the country.

Grain Growers' Western Australia regional co-ordinator, Alan Meldrum, said WA grain production is on track to reach average yearly levels.

He thinks WA is approaching 14 million tonnes of grain production this month, up from 13 million last month.

"The final total for WA is, of course, unknown, but what is obvious is that the total is going to be higher than forecast."

He said the improved grain production in WA will offset losses in eastern and southern states and balance Australian grain production to about average levels.

Mr Meldrum said that was "pretty impressive" and a testament to growers' "soil amelioration techniques, lime, timely planting and preparedness to take a risk".

He said "every season is a risk, but 2017 seemed more risky than any other season I can remember".

According to Mr Eastburn, most of Australia's wheat is exported and "there will be no shortage of bread on shelves in Australia anytime soon".

While NSW usually exports more than half of its crop, states such as Western Australia export closer to 90 per cent "because their domestic market isn't that big", Mr Eastburn said.