The 56-year-old man drove his Toyota Landcruiser into floodwaters on Tuesday night, before being sucked into a concrete pipe, NSW Police said.

Police and State Emergency Service volunteers later found his body in floodwaters.

Meanwhile, unions are calling on Prime Minister Scott Morrison to reintroduce JobKeeper for people in flood-affected regions in NSW.

JobKeeper was a temporary measure designed to keep Australians in jobs by supporting COVID-affected businesses with payments of $1500 per worker per fortnight to cover the cost of wages.

"The arguments that applied for COVID-affected workplaces also apply to flood-affected workplaces," Unions NSW Secretary Mark Morey said on Tuesday.

"We can't allow otherwise healthy businesses to fail because they've been hit by a crisis over which they had no control."

Premier Dominic Perrottet last week announced a $551 million support package for flood victims, including support for semi-permanent housing pods such as those used after the 2019-20 black summer bushfires and mobile motor homes.

"Emergency payments are short term measures. We need medium-term structural support, providing solid financial foundations," Mr Morey said.

The call came as Health Minister Brad Hazzard warned of serious biohazards for ocean swimmers after floods.

"We know when we've had big rains, the general advice is don't go surfing, don't go swimming in the open ocean for a day or two," Mr Hazzard said.

"When you've had a one-in-100-year flood, you might be wise to not go surfing with parasites, bacteria and diarrhoea."

Mr Hazzard said flooding and sewage outflows posed a risk of cryptosporidium, giardia, other parasites and bacteria.

"Normally you've got to fight somebody away from the surf - this time you might well be fighting off the parasites for diarrhoea," he said.

Australian Associated Press