Cathay Pacific has banned a Hong Kong couple from its flights after their row with a mainland Chinese traveller over her reclining seat.

The Chinese woman had complained on social media that she was harassed by the couple seated behind her on a Cathay flight after reclining her seat.

The Hong Kong flag carrier said on Sunday that it had added the couple to its no-fly list, saying it has "a strict zero-tolerance policy" towards behaviours that disrespect fellow passengers.

The Chinese woman's post on social media platform Xiaohongshu, which captured part of the confrontation, had garnered 194,000 likes as of Monday morning and drawn mixed reactions online.

The incident took place on a flight from Hong Kong to London on 17 September.

In her post, the Chinese woman recalled how the middle-aged couple - a husband and wife - had accused her of obstructing their view of the in-flight television and asked her to straighten her seat.

When she refused, the wife stretched her legs and put them on the armrests of her seat, then started scolding her in Cantonese and slapping her arm, the woman said.

"When she realised I couldn't speak Cantonese, she started calling me 'mainland girl' in a derogatory tone," she said.

The husband, who was seated directly behind her, "frantically pushed" the back of her seat, the woman said. Her video showed the seat vibrating.

Another scene showed the wife raising her middle finger at the woman.

The woman then sought help from a flight attendant, who suggested that she straighten her seat.

"I was shocked because it was not meal time, yet the flight attendant wanted me to compromise," the woman said. "I rejected the suggestion."

Several passengers who witnessed the incident criticised the Hong Kong couple's behaviour.

"Don't call yourself a Hong Konger, you bully," one passenger said.

Another said, "This is too much. How old are you? Why are you bullying a young girl?"

The woman's post on Xiaohongshu sparked similar outrage.

"If they want more space, they should have paid for first-class seats," one person wrote.

Several commenters were quick to defend Hong Kong's reputation, with one saying "Most people in Hong Kong are kind, this couple is an exception."

It has also triggered a debate on whether reclining one's aeroplane seat is an acceptable practice.

Several users said that it should be acceptable, given that the ability to recline is a built-in function of the seats.

Others said it can get uncomfortable when passengers in front recline their seats too far back.