AWB is seeking to clean out its share registry and get rid of more than 7000 shareholders.

But the Victorian Farmers Federation says if growers want a voice in AWB, now might be the time to buy, rather than sell, shares.

AWB has written to shareholders who have "unmarketable" parcels of shares with a total value of less than $500 as of January 9 this year.

If shareholders don't respond to the letter, their shares will be sold and they will be sent the payment.

AWB shareholders need to advise the AWB share registry by 5pm on February 27 whether they want to keep their shares, or they will be sold.

Last month there were 7943 unmarketable parcels, totalling 615,888 shares.

VFF Grains Group president Geoff Nalder said if grain growers felt strongly enough about AWB they should take the opportunity to buy enough shares to have a marketable parcel.

"They need to be shareholders if they want to have a say," Mr Nalder said.

"It's difficult for them individually to have enough to determine the direction of AWB, but if enough farmers feel strongly and have a parcel of shares then they can have a say."

Mr Nalder said while the AWB share price was low it was a good opportunity to buy.

Australian Shareholders Association chief executive officer Stuart Wilson said the opt-out method of selling the unmarketable parcels was not unusual.

He said the offer was advantageous to shareholders as they would not incur brokerage charges.

Mr Wilson said companies were often charged by share register companies about $30 per year per shareholder to manage the register.

AWB industry relations manager Ian Desborough said it was standard corporate practice to reduce the cost of the share registry.

"The question is: Why didn't we do it sooner?" Mr Desborough said.

Mr Desborough said the opt-out method was chosen because people with a small shareholding regularly ignored their mail.

He said he doubted many of the smaller shareholders would be current grain growers.

"Growers tend to have more than $500 worth of shares," he said.

He said many of the shareholdings dated back to 1989.

"There's been a lot of (grain grower) retirement over that period of time," Mr Desborough said.

AWB has almost 52,000 shareholders holding more than 352 million shares.

The AWB share price was $2.34 on Friday.