A woman has been charged over the death of a former business high-flyer who died days after being repeatedly bashed with a mallet.

Natalie Ann Reader Van Breugel, 45, appeared in the Waitakere District Court charged with the manslaughter of Lance Bain.

Police allege she hit Mr Bain "numerous times" with a mallet. She has also been charged with causing grievous bodily harm and threatening to kill.

It is understood Van Breugel and Mr Bain were in a relationship.