Three people have been burned - one of them critically - after an alleged Molotov cocktail attack in South Auckland. 

A 32-year-old woman from New Lynn was arrested following the Pukekohe incident, which occurred just after midday on Sunday, according to police. 

The woman is set to appear today at Manukau District Court, charged with threatening to kill one woman, assault with a Molotov cocktail of another woman and causing grievous bodily harm to a third person. 

If convicted, she could face up to seven years' prison for the threat charge, five years' prison for the alleged assault and 14 years for grievous bodily harm. 

"A Molotov cocktail was allegedly produced by one party and in the course of the altercation three people received burn injuries," a police spokesperson told the Herald. 

"One person is in Middlemore Hospital with critical injuries and two other persons received minor burn injuries." 

Police declined to comment further on the case because it is now before the courts.