More than 100,000 people have braved sub-zero temperatures to attend the opening day of South Korea's Hwacheon Sancheoneo Ice Festival to snatch trout with their bare hands and fish from a frozen river.

Organisers said at least 130,000 local and foreign visitors took part in activities on day one of the three-week festival. One of the drawcard events is bare-handed fishing, reports ABC News.

The rules are simple — participants have five minutes to use whatever means necessary to catch fish and stuff them in their shirts, to later be cooked on the grill or sliced up sashimi style.

One of those people was South Korean woman O Chul-Kyu, who attended the festival with friends and family.

‘I caught a trout with my bare hands. It's so much fun but a little bit cold though,’ she said.

The festival, which will continue until January 28, takes place in Hwacheon, 120 kilometres north of the capital Seoul in the northern province of Gangwon.

About 60 different events take place including sledding, ice soccer and the most popular activity, ice fishing on the river.

The Mayor of Hwancheon County said the event was popular with tourists, who he's anticipating an influx of ahead of the Winter Olympic Games being held in Pyeongchang of Gangwon province in early February.