Police are hunting a man and woman over an attack on another man in Melbourne's south-west.

The man, believed to be in his 50s, was assaulted, stabbed and left for dead in a home on Kookaburra Avenue, Werribee, about 11.30am on Wednesday.

Apprehension warrants for attempted murder have been issued for Corey Whittle, 39, and Samantha Vella, 25. Credit:Victoria Police

He was taken to Royal Melbourne Hospital in a critical condition, with "serious upper body injuries", an Ambulance Victoria spokeswoman said.

Apprehension warrants for attempted murder have been issued for Corey Whittle, 39, and Samantha Vella, 25.

Wyndham crime investigation unit detectives are appealing for public assistance to help locate the pair, who police believe frequent the Werribee and Hoppers Crossing areas.

Anyone who sees the pair are urged to contact triple zero.