Sydney-born Crusaders prop Michael Alaalatoa has extended his Super Rugby contract for a further two seasons.

Alaalatoa has enjoyed an impressive debut season for the second-placed side, making seven appearances off the bench to replace All Blacks tighthead Owen Franks.

The 24-year-old, who attended Sydney's Newington College, made just one appearance for the NSW Waratahs in two seasons.

Former Samoan under-20 representative Alaalatoa is the son of former Samoan international Vili and the older brother of current Brumbies prop Allan.