According to Korea Agro-Fisheries & Food Trade Corp., retail prices averaged 5,655 won ($5.01) for a pack of 30 eggs in September, down just over 20 per cent from 7,233 won in August and only slightly above the 5,590 won for September 2016.

The price has fluctuated wildly since bird flu broke out at the end of 2016, according to Nikkei Asian Review.

A pack of 30 at a large supermarket went for 9,096 won at one point, more than 60 per cent higher than the annual average in 2016.

The disease spread rapidly despite various government containment measures, such as restrictions on the movement of birds, disinfection and culls -- around 30 million chickens and ducks had been culled by the beginning of this year.

Even after the disease was brought under control, many eggs were discovered to be contaminated with insecticides, sparking consumer uproar and keeping prices high.

Intermittent outbreaks, including one in June, led to further spikes in prices.

Eggs tend to be more expensive at neighborhood stores as lower prices at large supermarkets push down the overall average.

When the average was hovering at around 7,000 won, a pack of 30 could go for around 10,000 won at a small- or medium-size supermarket.

At one such store in central Seoul, packs of 30 were recently seen priced at 7,600 won.

"Eggs have become a luxury item," said an employee.