Spencer spent his winters in the Northern Hemisphere, notably Monaco, where he was reported to base his 48.5 metre, €40m superyacht T6.
The vessel featured a hanger for a Eurocopter, making it at the time of its construction the only non-military New Zealand-registered vessel able to refuel helicopters at sea.
Fiercely private, Spencer regained a profile in recent decades during regular court battles with neighbours and councils over zoning and right of way access.
His fight to prevent members of the public and tourists crossing his farmland to get access to Waiheke's Stony Batter gun emplacements entered Auckland folklore. The bitter battle lasted almost two decades during which he barricaded roads with earthen ramparts.
After 19 years the clash finally concluded at the Privy Council where Spencer lost.
The Spencer family is the largest landowner on Waiheke, who last year went to the High Court to prevent large tracts of their holdings being designated "outstanding natural landscapes" and subject to restrictions on development. The family also owns Rangipukea lsland off Coromandel and has substantial property holdings at Stanley Point on the North Shore.
Spencer family businesses recently bought Lochinver Station, stepping in after preferred bidders Shanghai Pengxin were rejected by the Overseas Investment Office.
Spencer is survived by his son Berridge and daughter Mertsi. Berridge has become the public face of Spencer family business interests, while Mertsi is understood to run a specialist home accessory business in Dubai.