Japan airlines
Japan Airlines Boeing 767-300 plane is towed at Tokyo's Haneda airport Kazuhiro Nogi/ AFP

Japanese customs officials arrested a group of Korean tourists who attempted to smuggle gold bars hidden in their rectums, according to newspaper Asahi Shimbun.

The seven women, all aged in their 50s and 60s, were stopped by staff at Chubu International Airport who discovered the precious metals following an X-ray examination.

Border security said the would-be smugglers had hidden five to six roundish blocks inside plastic bags, each weighing around 200 grams.

Authorities subsequently confiscated the gold and say the group must now pay a large fine for attempting to avoid a strict consumption tax levied on imported goods.

The women, who had travelled from Incheon International Airport in South Korea last January, will be reunited with the items once the penalty is paid.

Japan has seen a huge increase in smuggling since the introduction of a 3% levy by the Finance Ministry's Customs and Tariff Bureau in 2014.

Nationwide tax evasion rose by 40% between July 2016 and June 2017, totalling 870 million yen (£5.794 million). Officials said there was a 60% increase in smuggling over the 12-month period with an estimated 467 cases of attempted smuggling and tax evasion.

Although incidents of smuggling are on the up, authorities say it is rare for goods to be brought through airports internally by passengers.

Three-quarters of all documented cases hide goods externally around the person while others involved hiding gold inside luggage or suitcases.

Last year, six people were arrested after they they stashed bars of gold in an airplane toilet in a bid to circumvent customs law. The discovery, which occurred in June of 2017, unveiled five kilograms worth about 22.8 million yen ($209,000).