A district councillor said on Monday that it was unprofessional of a security guard to refuse to open the gate of a residential complex in Tseung Kwan O to allow an ambulance to enter last week.

Video footage shared online showed the guard at Fu Ning Garden arguing with residents about the ambulance's arrival and asking paramedics to walk to the person waiting for help instead of driving to them.

The guard was subsequently suspended.

Sai Kung councillor Andrew Chan, who's also a resident of Fu Ning Garden, said vehicles normally use another entrance to the complex but there could have been traffic congestion there because of works.

"Even though it was an emergency, she [the guard] might have just focused on the fact that she hadn't opened the gate for the many years she's worked there," Chan said on Commercial Radio.

"The judgement at that time was wrong, it's unprofessional. Her subsequent quarrel with residents was even more unacceptable."

A former head of the Association of Property Management Companies, Johnnie Chan, said the way the guard handled the matter was undesirable, as was the way she spoke to residents.

He said on RTHK that frontline staff should be given guidelines on what to do in emergency situations.