A Czech tourist was stabbed in what appears to be an unprovoked attack at a backpackers in Motueka, 54km northwest of Nelson, overnight.

The man suffered a minor wound to his leg as he fought off his assailant.

An American who was bunking with the victim witnessed the 12.45am attack but was unharmed.

There appeared to be no motive for the attack, said Detective John Nicholls, of Motueka CIB.

A 38-year-old New Zealander has been charged with wounding and will appear in Nelson District Court this morning.