A viral video of a Chinese mainland mother defending her toddler for urinating into a diaper on a Hong Kong street has reignited friction and debate between the fragrant city's residents and mainland guests.

A mainland girl, about 2, urinated on the street in Mongkok while traveling with her parents on April 15, Hong Kong media reported last week.

When a young man photographed the scene "out of discontent at the behavior," the girl's parents fought with him to remove his memory card, the Hong Kong-based Sing Tao Daily reported on Saturday.

Police arrested the mother for assault, reports said.

Video footage shot by passers-by posted later online showed the mother clutching a diaper and then putting it into a bag. She placed the diaper beneath the girl to stop her urinating on the street, a Phoenix TV report revealed on Tuesday.

"I tried to use the bathroom but there was a long line," she explains to onlookers in the video. "My child wanted to pee so badly, what should I do?"

Many Net users called for a cap on travel permits issued to mainland travelers after seeing the "barbarous" behavior on video, the Sing Tao Daily reported on Saturday.

"Why don't the couple let the child wear the diaper as a precaution in the first place?" tweeted Net user Ivan lam.

"They could talk to the people in the line to let them use the bathroom first or let the child pee inside the bathroom instead of on the street."

Reports have been widely read and forwarded in recent years of mainlanders misbehaving that include littering, eating noodles on the subway and buying up baby milk powder.

But mainland Net users fired back at Hong Kong citizens' treatment of the couple and the child.

"The man had no right to take pictures of a little girl peeing and violate her privacy," wrote Net user youyouyu on China's Twitter-like service Sina Weibo on Tuesday.

Other Weibo users argued Hong Kongers should be more tolerant of the parents for using a diaper.

As of press time, an online poll on Sina Weibo showed about 85 percent of more than 140,000 voters believed Hong Kongers harbor prejudice against mainlanders and that it was understandable to let the child urinate on the street.

Hong Kong people were "overdramatic in this case," Zhu Shihai, a professor from the Central Institute of Socialism, told the Global Times on Tuesday.

"Some Hong Kong citizens, especially the young, have no cultural identification with the mainland and they have always seen mainlanders as uncivilized people," Zhu said.

People with vicious intentions have deliberately upgraded a simple incident into a conflict, Zhang Dinghuai, a professor at the Contemporary Chinese Politics Research Institute of Shenzhen University told the Global Times.

They were trying to inflame the feud, he warned.

Sing Tao Daily quoted a Hong Kong lawyer as saying urinating in public can earn a 500 yuan fine or three months' detention, but children under 10 with no criminal intent are excluded from the rule.