Police said on Saturday a teenager and two men have been arrested for allegedly wounding a 20-year-old man with a cutter in Admiralty on Wednesday night after mistaking him as their target in a dispute over money.

The three, aged between 18 and 27, are suspected of causing grievous bodily harm with intent, conspiring to cause grievous bodily harm with intent and possessing dangerous drugs.

Officers said they found a 15-centimetre-long cutter along the alleged escape route.

They also discovered five packets of suspected ketamine on a suspect and a small amount of other drugs, including suspected cocaine and cannabis oil, at the home of another of those arrested.

The force is alleging the 27-year-old paid the other two to carry out the attack.

Senior inspector Chan Pik-shan said the suspects, who have a triad background, would be taken to Eastern Magistrates' Courts on Monday.

"Police believe the victim got attacked because he was mistaken as another person due to a similar appearance and body shape. Our arrest operation will continue," he said.

"We have already identified two people who are believed to be the masterminds. They are already on the wanted list."

Chan said the SmartView programme, which has seen surveillance cameras installed across Hong Kong since last year, helped officers crack the case within a short period of time.

The victim is in a stable condition in hospital.