Police have "relentlessly" targeted reporters as three newsmen were directly hit by a water cannon during Wednesday's handover rally, Hong Kong Journalists Association chairman Chris Yeung Kin-hing said.

Yeung expressed his worries yesterday by saying the national security law appeared to be a new tool for authorities to rein in the press, clearing the way for tighter controls and regulation of so-called "fake news."

He added: "Although current laws protect the freedom of the press, the national security law overrides all local legislation.

"So it is questionable whether the national security law can request media organizations to hand out their information [material they collect]."

On the three journalists who were injured, Yeung said it was "impossible" for the police not to notice their reflective press vests.

"In almost every operation, journalists have been targeted by the police with pepper spray, eviction, and they would try to move journalists away from the scene," he said.

Among the three injured was a Flash Media Hong Kong photojournalist, who was hit directly in the head, the online media company wrote in a Facebook posting.

The male photojournalist flew two meters and fell after being hit on Hennessy Road in Wan Chai.

A reporter and a photojournalist of Apple Daily were also hit three times continuously within a space of 20 seconds, the paper said yesterday in a Facebook post.

"I can feel that it was directly aimed and shot at my head," the reporter said yesterday. "The water directly entered my left ear canal, and when I wiped my nose I noticed my nose was gushing with blood."

The reporter said there were around four journalists and no civilians at the scene near Tin Lok Lane in Wan Chai at around 2pm.

The photojournalist suffered from allergies and redness on the skin, and felt a "burning sensation all over the body" after the hit, according to the paper.

Next Media Trade Union condemned the police in a statement yesterday, saying the police deliberately wounded people with repeated water cannon hits toward their journalists, and senior police officers had "connived" with their colleagues to attack reporters. The union demanded an apology and an explanation from the police.

Cops draw fire for targeting journalists with water cannon