The billionaire Besen family has offloaded a quarter stake in one of Australia's largest malls, the Highpoint Shopping Centre in Melbourne's west, for $680 million.

The sale of its share in the lucrative shopping mall to diversified property giant GPT will significantly boost the family's wealth, estimated by the BRW Rich List to be about $2.4 billion.

Marc and Eva Besen founded clothing retailer Sussan Group. Credit:Tim White

The family, headed by patriarch Marc Besen, decided to sell its 25 per cent holding in the mall and the neighbouring Maribyrnong Homemaker centre in April.

GPT's Wholesale Shopping Centre Fund picked up the Besen's share after taking up a "pre-emptive" purchase option.