Indonesian authorities have arrested a German for allegedly trying to smuggle 239 grams of cocaine, some of it in his stomach, into Bali.

Hans Peter Naumann, 48, was arrested on Friday after he arrived on a flight from Bangkok, customs official Djarot Utomo said.

Officers ordered x-rays of Naumann after suspecting something was hidden in his stomach, Utomo said on Saturday.

Eleven white capsules filled with cocaine were found in Naumann’s underwear, and doctors found six others inside his stomach, together worth $US65,000 ($A70,330), Utomo said.

Police are investigating and Naumann hasn’t yet been charged.

Indonesia has strict drug laws and convicted smugglers are often sentenced to death.

More than 140 people, about one-third of them foreigners, are on death row, mostly for drug crimes.

Last year, a British woman was sentenced to death for smuggling $US2.5 million worth of cocaine into Bali in her luggage.