The former lover of movie star Jackie Chan has been arrested after allegedly hitting her daughter.

Elaine Ng Yi-lei was "arrested on suspicion of cruelty" to a child, a police source said on Friday, according to a report in the South China Morning Post.

The source said Ng's daughter, Ng Cheuk-lam, told staff at her school that she had been assaulted by her mother and that they reported the case to the police.

Ng claims that Cheuk-lam is Chan's child.

After preliminary investigations, police suspected that Ng may have hit her daughter on the arm at their home in Tai Po, the SCMP said, and arrested Ng on Wednesday.

The girl did not appear to have any visible injuries, police later said.

According to the SCMP source, a search of Ng's home revealed a small amount of what appeared to be illegal narcotics, but further tests were needed.

The source said police needed to carry out further investigations to establish whether it was Ng, her daughter, or their domestic helper, who possessed the substance.

Ng was released on bail and asked to report back to police in mid-May.

In an interview with local media at her home on Friday, said the SCMP, Ng - speaking from behind window blinds - said her daughter was still in hospital but insisted she had not abused her.

"Children are sometimes naughty, and they do something wrong when they are naughty," Ng was heard saying in a video clip of the interview.

"I think adults can deal with these things… But first (of all), I did not hit her like that, and secondly, she did not keep drugs."

In January, Jackie Chan's son, Jaycee, 32, was jailed for six months and fined 2,000 yuan (S$430) in Beijing for accommodating drug users.

Jaycee tested positive for marijuana, and a stash of marijuana - 117.72g of it - was stashed in a safe in a bedroom.

Elaine Ng is an actress and was the winner of Miss Asia, a beauty pageant hosted by ATV, in 1990, said the SCMP. She announced that she was pregnant in 1999 and disclosed that she had an affair with Jackie Chan after public speculation. Jackie Chan, in response, said he had "only committed a fault that every single man in the world commits".

Chan's current employer, online radio station DBC, said it would keep close track with the development of the event but would not comment because it had entered legal process, the SCMP reported.