The Watagans National Park had been drenched in heavy rain when a woman in her 30s was struck by a falling tree branch and died last night.
Police said she was bushwalking in the National Park at Cooranbong, near Lake Macquarie, when the incident occurred.
Emergency services, including Lake Macquarie Police, Ambulance NSW, Fire and Rescue NSW and the Rural Fire Service, were called to the area at about 6:30pm.
A report will be prepared for the coroner.
The National Parks and Wildlife Service said it would not comment on the incident while the facts were still being determined and it remains under investigation by police.
The service also would not confirm whether the incident occurred at or near the Bangalow Campground, which is currently closed to the public.
Large parts of the Watagans National Park are closed, with alerts issued for Gap Creek and Gap Creek Falls walking tracks as well as several campgrounds.
The areas have been closed off due to storm and road damage, landslides and major upgrades.
A spokeswoman said the closures in the park were not due to the heavy rain over the weekend and had been in place for several months.
Lucky escape from floodwaters
Further north in the Upper Hunter, a man who tried to drive through a flooded creek crossing has been rescued from the roof of his ute in Merriwa.
Paramedics and emergency services were called to the causeway on Idaville Road over the Krui River at 6:30 this morning.
Deputy captain of the Merriwa Rescue Squad Andrew Luke said the driver was lucky the ute came to rest on the edge of the causeway, leaving the top of the vehicle above the water line.
"Thankfully the rocky side of the causeway has caught the vehicle and stopped it being swept further downstream," he said.
The rescue was a team effort involving police, ambulance service and the Volunteer Rescue Association.
Mr Luke said people needed to use their better judgment and stay clear of rising water.
"It's an unfortunate situation … we've had to endanger the safety of numerous personnel just to get them back to safety," he said.
"Stay out of floodwaters, it's not a game, as this person found out. They can be much more intense and cause a lot of damage despite them perhaps being [over] a familiar crossing."
