South African billionaire and businessman Douw Steyn, who founded the BGL Insurance Group and was a good friend of late South African statesman Nelson Mandela, has died aged 72.

Steyn, known for his global success in the insurance industry, died on Tuesday following a long period of poor health.

He was regarded in South Africa as a "visionary" and an "exceptional entrepreneur".

Steyn first befriended Mandela shortly after the former president was released from his decades-long imprisonment on Robben Island.

Steyn's death was confirmed by Steyn City Properties, the company behind the eponymous luxury golf estate he founded and developed.

The sprawling residential lifestyle estate is located in the northern part of Johannesburg and was designed to "create a self-sustaining community", according to South African online news website Daily Maverick.

"It is with profound sadness that we announce the passing of the visionary behind Steyn City," the company said in a statement.

It added that Steyn would be "remembered as an exceptional entrepreneur who built a global business of immense scale across seven countries".

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The Nelson Mandela Foundation described the Steyn as a "larger than life character" and "someone Madiba [Mandela] regarded as a friend".

After his release from prison in 1990, Mandela spent six months at Steyn's former home in the affluent Johannesburg suburb, Saxonwold, where he edited his autobiography Long Walk to Freedom.

"He [Steyn] supported Madiba in numerous ways over many years. During 1992 Madiba lived in [Steyn's] home as he navigated his way through a very painful separation from Winnie Madikizela-Mandela."

South Africa's first democratically elected president also turned to Steyn "when he needed spaces for retreat or support for his projects", according to the foundation.

Mandela spent 27 years in prison for campaigning to end white-minority rule.

Eighteen of those years were spent on Robben Island, an island off Cape Town.

Steyn began his entrepreneurial journey in 1975 when he founded Steyn's Insurance Brokers, according to another local news website BusinessLIVE.

This would pave the way for the establishment of one of the country's leading insurance groups, Auto & General, and later BGL Insurance in the UK in the 1990s. BGL is the parent company of popular price comparison website Compare The Market.

Auto & General was later incorporated into the Telesure Investment Holdings group, which offers a variety of financial service products in countries such as Australia, Turkey and the UK.

Outside his business ventures, Steyn was known for his philanthropy. His family trust donated large sums to South Africa's Covid-19 relief efforts, with a considerable amount going towards supporting small businesses and providing food security for families affected by lockdown.

The Steyn Foundation, established through Steyn City Properties, also supports impoverished townships.

He leaves behind his wife and three children.