A veteran spearfisher has described the moment he had a close encounter with a five metre great white shark while swimming off the NSW coast.

Emanuel Bova was spearfishing in the water off Royal National Park, just south of Sydney, on Friday afternoon when the predator emerged from the depths heading directly at him.

'He came past me, I realised and just went ''whoa,'' it just blew me away. That's when my heart started racing and I realised I'm dealing with a beast,' he told Nine News.

While Mr Bova is an experienced spearfisher who has seen many sharks close up, he said this encounter was a first.

'I'm swimming back to the jet ski and there's just this huge (great) white,' he said.