The fourth fire in under a month broke out at the Nam Sang Wai wetlands in Yuen Long on Monday, damaging a dock at the ferry pier and destroying a boat.
The fire was discovered at around 6am by a ferry operator who called police after noting that a wooden platform was on fire, according to Apple Daily.
Firefighters put out the blaze about ten minutes after they arrived on the scene. No one was hurt, but the fire destroyed a boat that was tied to the dock – it later sank.

According to the police, firefighters believed the cause of the fire was suspicious after a preliminary investigation. The case, classified as arson, has been handed to the Yuen Long district crime squad for investigation. No arrests have yet been made.
Nam Sang Wai is a popular spot for local visitors, as well as a resting spot for migratory birds. Ferries at the pier take passengers across the Shan Pui River from 6am to 11pm. The fire did not affect the pier’s operations.
Government departments and the police stepped up patrols after the area was hit by three fires last month. Fires broke out on March 12, 13, and 22, affecting more than 12 hectares of land.

A spokesperson for the police told HKFP that the police were still investigating whether the three fires were linked.
Calls for arrests
In a Facebook post, Lam Chiu-ying – a Chinese University adjunct professor and former director of the Observatory – urged police to investigate, saying the spate of fires showed traits of organised crime.

“Another fire at Nam Sang Wai, this time personal property was destroyed, and transportation was damaged… it is seeming more and more like there is a mastermind and showing traits of organisation.”
“I respectfully ask the police to investigate in the direction of ‘organised serious crime’ and arrest the offending criminals – [they] must stop taking the attitude of ‘this is the way it is’ because this is the New Territories.”

Lam told Apple Daily that he was worried about the fires’ impact on Nam Sang Wai.
“It happened again and again, it seems as though there is a strong will behind it to continue carrying out the matter.”
Lawmaker Roy Kwong said: “It’s very hard to make people believe that this was a natural fire… this is arson. There’s been fires again and again at Nam Sang Wai, we should find the pyromaniac behind it.”
Nam Sang Wai was previously scorched in December 2016, as a consultation on development plans for the area drew to a close. The police launched an investigation but no-one has been arrested.