Emergency services are praising the heroic actions of two teenagers who rescued a woman from a car submerged in a Christchurch lake this morning.

Photo: Google Maps

Fire and Emergency's Wigram senior station officer Peter McGrail said the boys, Jake and Joseph, jumped into the water to help after a woman drove into the lake about 8.15am.

He said the lake was 20m deep, the water was probably about 2 degrees and the car was a long way from shore.

When he arrived he could only see bubbles emerging from where the car was, and it was not possible to save the woman's two dogs.

But the two boys, who were on their way to school nearby, managed to get the woman to shore.

Mr McGrail said the actions of the boys definitely saved the woman's life.

The car has been removed from the water.

A similar accident in the same lake led to the death of a Christchurch couple in 2017.