The arrest of an 83-year-old woman for theft and a man aged 75 for assaulting a child in separate incidents have highlighted the growing problem of crime committed by the elderly in Japan.

The National Police Agency reported in July last year that crimes by pensioners had outstripped offences by juveniles in the first half of the year for the first time ever, with a significant proportion of the arrests for violent crimes.

Adding to the police statistics, Sato Kamiyama, 83, was arrested in Tokyo's Ueno Station on Friday after being caught pickpocketing a wallet from a woman who was shopping.

"If I see a wallet, I'll take it," the suspect was quoted by TV Asahi as telling police. "I did it for the money."

Mrs Sato is apparently notorious with police in the district – allegedly, her preferred method is to target women shopping in the food halls of department stores – and has been questioned on at least 20 other occasions over thefts.

On Sunday, police questioned a 75-year-old man in the city of Kakogawa, central Japan, after a boy of six accused him of grabbing him around the throat and choking him.

The boy claimed the man, who has not been named, attacked him after he and some friends told him not to drop his cigarette butts on the street.