A Melbourne mum who killed three of her children after intentionally driving the family car into a lake will be re-sentenced.

Akon Guode was jailed in 2017 for 26 years and six months after she drove into a Wyndham Vale lake, killing her four-year-old twins Hangar and Madit and 16-month-old son Bol.

She also pleaded guilty to the attempted murder of her daughter Alual, 5, who was in the car but survived after being pulled from the water.

That sentence, however, was slashed by Victoria’s Court of Appeal in August 2018 to 20 years with a minimum of 14.

Prosecutors appealed the reduced sentence to the High Court, which ruled in their favour on Wednesday.

In a 3-2 split decision the majority of judges found the Court of Appeal was wrong to reduce the sentence.

The case will be returned to the Court of Appeal for Guode to be re-sentenced.

She had survived rape and her soldier husband’s death in war-torn Sudan before coming to Australia as a refugee.

-AAP