Egg prices in South Korea have hit a 20-year high as the avian influenza outbreak is significantly disrupting supplies.

According to Korea Agro-Fisheries and Food Trade Corporation on Monday, the average retail price of a carton of 30 eggs stood at seven-thousand-37 won, or about five dollars and 86 cents, as of last Thursday.

It is the first time the price of a carton surpassed seven-thousand won since the agency began compiling related data in 1996.

According to retailers, egg prices have continued to go up since last Thursday and were selling at seven-thousand-510 won for 30 on Monday. At some shops, the price soared to more than eight-thousand-800 won, up to 58 percent from a year earlier.  

The production prices of eggs also shot up by 77 percent to five-thousand-511 won.

More than 20-point-four million egg-laying hens have been culled since the bird flu outbreak last month, accounting for four out of five such chickens culled.