A significant change to McDonald's breakfast menu has been disclosed amid Australia's devastating avian flu outbreaks and egg shortage.

Rather than continuing to serve breakfast till the usual noon hour, from Tuesday, the notable fast-food business will halt its operations at 10:30 a.m.

The decision was the result of the multiple avian influenza outbreaks, which since May has led to the culling of around 1.5 million chickens from 11 farms in the southeast, Reuters reported.

McDonald's has made changes to its breakfast menu in light of the avian influenza outbreaks in Victoria, NSW, and the ACT.

"Like many retailers, we are carefully managing the supply of eggs due to the current industry challenges," a company spokeswoman said. Our network of Australian farmers, producers, and suppliers remains our primary partner as the sector rallies to meet this challenge."

Amid an epidemic of avian flu that was impacting egg supplies, Ritchies IGA's Fred Harrison reported a consistent supply, but cautioned about price rises because of increased demand.

Last month, Coles and Woolworths placed restrictions of two cartons per person on the purchase of eggs.

A Woolworths spokesperson said, "We're expecting a short-term delay in stock from one of our egg suppliers in NSW, ACT and Victoria due to the temporary closure of one of their packing sheds. Their supply is expected to recover towards the end of the week as they ramp up operations at their other sites."

Though demand has soared, Joel Owin, the owner of White Swan Eggs farm near Agriculture Victoria's restricted zone, is still confident about supplies.

"When the first outbreak happened in Meredith, there was a surge in egg sales about one to two weeks after that. ... We noticed at the farmers markets that the average sale, or the amount of dozens people were buying, were up. But people were more concerned about how we physically were and hoping we stay virus free because if we do get the virus here all of our chooks will need to be culled which would end our production," ABC reported.