Police say two 17-year-olds are in police custody in Nelson after threatening a British man with a knife yesterday evening.
The 20-year-old tourist was hitchhiking alone when he was confronted by the teenagers at about 7.30pm.
Police said the pair threatened the hitchhiker with a knife and demanded money.
They said the tourist handed over a quantity of cash, and was left shocked but unharmed.
The teenagers have been charged with aggravated robbery and are due to appear in the Nelson District Court on Saturday.