A 16-year-old boy is in police custody after another 16-year-old boy was fatally stabbed in Oamaru last night.

The boy died near the intersection of Exe and Thames Streets, Oamaru, about 10pm despite efforts by police to resuscitate him, Dunedin Senior Sergeant Brian Benn told NZPA.

Another 16-year-old boy had been taken into custody in Oamaru in relation to the incident.

Mr Benn said he was unsure what the relationship between the two boys was.

The scene remained cordoned off and was under guard.