A man has died and a woman is in hospital in a serious condition after being assaulted outside a Northern Territory shopping centre.

The 20-year-old man is understood to have been stabbed with a serrated knife in the Darwin suburb of Karama about 11pm Wednesday.

Paramedics transported the man to hospital where he pronounced dead upon arrival, NT police said on Thursday.

A woman, 25, was also taken to Royal Darwin Hospital with significant injuries to her stomach and remains in a serious but stable condition.

Two men are in custody and are assisting detectives.

A crime scene has been set up outside the Karama Shopping Plaza on Kalymnos Drive.