Locke's three-year contract with Salford was announced in May and he was due to link up with the Red Devils after this NRL season.
The parties have since been negotiating an early release.
Warriors football operations manager Dean Bell said Locke was keen to head abroad immediately.
"We're happy for Kevin to be released now. It will enable him to settle into life in England and establish himself with his new club," he said.
Locke said he was sad to be leaving the Warriors but was looking forward to the move.
"I've got plenty of great memories from my time here and I want to thank the club for all the support," the fullback said.
An eight-Test Kiwi, the 25-year-old Locke made his NRL debut five years ago, playing 89 times for the Warriors and scoring 26 tries.
However, injury and the arrival of England international Sam Tomkins have restricted him this season to two appearances, both away from his favoured position.
