The Korean Federation for Environmental Movement claims to have carried out research on levels of acrylamide in french fries from five fast food companies as well as potato chips made by five different Korean manufacturers.
KFEM's report suggests that the fries had an average 1,620 micrograms of acrylamide per kg and the potato chips had 1,004 micrograms per kg.
The amount of acrylamide in French fries is higher than that found by the Korea Food and Drug Administration (KFDA) in 2002, noted the environmental group.
Back then, KFDA's research showed fries contained an average 980 micrograms of acrylamide per kilogram while potato chips 985 micrograms.
Acrylamide, a chemical found in glue and paint, can form in foods when starchy products are baked, roasted, fried or toasted. It first hit the headlines in 2002, when scientists at the Swedish Food Administration reported unexpectedly high levels of the substance, found to cause cancer in laboratory rats, in carbohydrate-rich foods.
The findings triggered a wave of new studies into how the chemical can be reduced in foods although it is still not clear how much harm consumption of small doses poses to humans.
In response to the new study, KFDA said it has not yet been determined whether acrylamide levels found in the chips and fries would harm health.
The KFEM referred to the limits on acrylamide levels in drinking water, set by the World Health Organization (WHO), as an indicator of its risk, however.
The group told the Korea Times that the quantity of acrylamide in one 114g bag of McDonald's fries was equivalent to the WHO-recommended amount in 580 liters of water.
WHO recommends no more than 0.5 mcg of acrylamide per litre of drinking water.
McDonald's fries had 2,540 micrograms of acrylamide per kilogram, the highest among the surveyed products.
Lotte Confectionary's crisps had the largest amount among the potato chips, at 1,950 micrograms, although the firm said it stopped producing this product early this year.
"Having three packages of Lotte potato chips or one and a half bags of McDonald's french fries is the same effect as drinking 2 litres of water containing more acrylamide than the WHO standard everyday for one year,'' a member of KFEM told the paper.
The group called on the government to set up measures to reduce acrylamide in processed foodstuffs and limit the amount of the chemical.
"The government should conduct regular research on quantities of such chemicals in food products and open the results to the public,'' the group told the paper.
"We are working on evaluating whether it is dangerous or not in the first place. After the research, we will regulate the level," Kim Dong-sul, senior researcher of the Korea Food and Drug Administration, told the Korea Herald.