A native flower walk that took volunteers seven years to plant was in the direct path of a bush fire that erupted in the southern reaches of Belmont Wetlands State Park last week.
Police are yet to determine the cause of the blaze that burnt through 79 hectares of bushland and threatened properties on the park's perimeter.
Park officers from Belmont Wetlands say a "Wildflower Walking Trail" was destroyed in the flames.
Clinton Smith, the park's operations coordinator, said volunteers and staff had planted over 40 species of native flora along the 1.5 kilometre track.
"All the wildflowers planted there have been lost unfortunately along with signage. That's the main trail to have been lost. All that track was in the main part of the fire," Mr Smith said.
It was difficult to assess the full extent of the damage to the track, he said, because some of the plants "actually go well with fire" while others do not.
Many of the flowers were set to bloom in September with the onset of spring.
"It is disappointing," Mr Smith said. "We had a wildflower walk event planned for next month that is quite significant. It's been held for the past four years. That can't go ahead now," he said.
Mr Smith said the beach access track was open at the park, however, he advised visitors not to enter the Wildflower Walk or Blackbutt Loop. Lake Macquarie council re-opened the portion of the Fernleigh Track that runs through the park on Monday afternoon.
"Anyone willing to attend to help and clean up rubbish after the fire would be much appreciated. Please contact us," Mr Smith said. "Once we clean up and go through a risk assessment for the [Wildflower] track we'll be looking at replanting.
"I want to pass a big thanks to the Firies for their help during the fire."
Chief Inspector David Matthews of Lake Macquarie Police District said officers were continuing an investigation into the blaze. He said its cause was "undetermined".
Greg Windbatt, the acting area commander of the Hunter, Newcastle and Central Coast for Fire and Rescue NSW said flames were completely extinguished by Saturday midday, after the fire ignited at the end of Merview Street on Thursday. No properties were damaged in the fire. He said firefighters did a "great job" in the marshy conditions, which prevented access to some areas of the park on foot and via truck.
Mr Windbatt said he was present at the fire ground during NSW Fire and Rescue, RFS and police officers' preliminary investigation into the cause. He said there was "good reason" for police to be involved in an ongoing investigation. However, he said he could not elaborate.
