wheat
© ABC News: Jo PrendergastGrain Growers Association chairman John Eastburn says damaged crop will only be good for stock feed.

The Grain Growers Association (GGA) says the recent wet weather has devastated wheat crops across Queensland, New South Wales and Victoria.

A report by the Commonwealth Bank reveals the national harvest is expected to be pared back from 25 million to 22 million tonnes.

It says the "disruptions to the harvest this year and the implications for quality are the worst for a lifetime".

The loss of crops is also expected to have implications for some of Australia's staple foods.

GGA chairman John Eastburn says it has been a tough time for farmers.

"The crop here is well and truly shot and sprung and [there is] very little quality left in it," he said.

"I'll probably harvest a little bit for stock feed, but that's about it."

Mr Eastburn says the loss of the crops will hit hard.

"Reasonably devastating for ... all New South Wales and Victoria and Queensland just coming out of the drought. It is a major devastation," he said.

Even those farmers who can harvest have seen their crop quality downgraded to stock feed.

That fetches about $100 less per tonne - half or even less than half of what they were expecting.

Mick Keogh, the executive director of the Australian Farm Institute, says it could get worse.

"If the rain continues and you get mould, in fact it will be downgraded further," he said.

"The original estimate was about a $3 billion winter grain crop, and I think some of the estimates are that about a third of that might be lost at this stage.

"Now if we get further heavy rains during this week, the damage will get even worse and that is only in New South Wales. You'd probably see similar losses in parts of Victoria and South Australia as well."

An analysis by the Commonwealth Bank reveals an expected drop in wheat exports from 16 million to 14 million tonnes.

Commodities strategist Luke Matthews says the national harvest is also expected to drop from 25 million to 22 million tonnes.

"Many in the industry are suggesting that the disruptions to harvest this year and the implications for grain quality are in fact the worst for a lifetime," he said.

"We estimate that harvest is at least one month behind schedule and we also estimate that at least 6 million tonnes of wheat will be of downgraded quality this year."

There is still a question mark over the ability of Australian bread makers to meet demand with local wheat, with gluten already being imported.

Mr Matthews says he expects there will be sufficient volumes of milling wheat for local purposes.

But Mr Eastburn is not so sure.

"The weather-damaged wheat is virtually no good ... so they will have to access it from somewhere," he said.

And one farmer's pain is not necessarily a gain for another.

Mr Eastburn says the predicted abundance now of low-grade wheat for stock feed is not necessarily a boon for stock producers.

He says the quality may be so low that stock producers will probably have to spend the money they have saved on supplements.