The small island, east of Port Macquarie, NSW, is a popular tourism destination and home to rare and threatened plants and animals.

The Lord Howe Island Board released a statement on social media on Wednesday that the "Permanent Park Preserve (PPP) is temporarily closed" and "cannot be accessed via recognised access points, bush tracks, or boat". 

The PPP covers about 70% of Lord Howe Island and was created to preserve the island's native flora and fauna. 

Cafe operator and treasurer of the local tourism association, Stephen Sia said the last-minute shutdown came as a surprise.

"There are about three or four groups already on the island in the middle of all the walks and the shutdown means they can't do their walks and all their schedules are disrupted," Mr Sia said. 

He said it was a popular time for walking groups and birdwatchers.

"It's a busy time of the year leading up to Easter and there have been requests for refunds and all sorts of compensation," Mr Sia said.

'Ecological threat':

Myrtle rust is a highly infectious plant disease that affects the endemic Myrtaceous species that are present in many plant communities on the island. 

The Lord Howe Island Board said the invasive fungus could impact iconic plants including the mountain rose and scaly bark trees, as well as world heritage values and the tourism experience.

"The rus has the potential to change the way our mountains and forest looks, it may alter food webs and ecology, and potentially affect world heritage values," a board statement to residents said.  

The board said myrtle rust was discovered on the island on February 3.

"Infected sites have been identified in three additional locations during settlement-wide sweeps that have been occurring weekly," the statement said.

It said necessary care was being taken to "manage this ecological threat".

Shocked holiday-makers:

Newcastle resident Vanessa Wills, who has previously volunteered on Lord Howe Island to help remove asparagus fern, had planned a holiday to the island in May. 

She said the PPP closure was a "shock".

"I cannot see how tourists can be expected to go when the island is essentially off limits. If I wanted to go to the beach, I would stay in Newcastle," Ms Wills said. 

"I feel very sorry for people whose departure is in the next week or two and think that they should be offered alternatives."

Myrtle rust experts from the NSW Department of Planning and Environment and Department of Primary Industries are set to hold an information session on the island on Thursday, March 16.

Original Story By | Luisa Rubbo and Madeleine Cross