A hero policeman who joined a tradesman who can't swim to save an elderly couple from their sinking car says they had said their final goodbyes as it slipped beneath the water.

The elderly couple from South Australia lost control of their car and careered into O’Keefe’s Dam in Creswick, north of Ballarat, on Thursday.

Leading Senior Constable Simon Barker helps secure the car as it is removed from O'Keefes Dam. Credit:Kate Healy/The Courier

They were rescued thanks to the bold and rapid actions of a passing tradesman and Leading Senior Constable Simon Barker who worked to free them before the car was completely submerged.

Speaking on Friday after visiting the couple at Ballarat Base Hospital where they're recovering, Senior Constable Barker said the couple "were resigned to the fact that they weren’t going to live.’’