Sir Michael Hill is stepping down from the helm of his business chain, Michael Hill Jeweller, to undergo cancer treatment

Andrea Slingsby has been appointed alternative director while he takes a leave of absence.

The 86-year-old opened his first store in Whangarei in 1979 at 40, after working in his uncle's jewellery store for nearly two decades.

The chain now has nearly 300 stores across New Zealand, Australia and Canada.