Secretary for Environment and Ecology Tse Chin-wan on Sunday defended the government's proposal to raise the fines for littering and illegal shop extensions, saying heavier penalties are needed to provide a deterrent effect.

The government has proposed doubling the fine for littering to HK$3,000 and raising the fine for illegal shop extensions from HK$1,500 to HK$6,000.

Speaking on a television programme, Tse said current penalties have not been reviewed for years, and they need to be beefed up to have a stronger deterrent effect.

"It's not about how much the penalty is, it's about what we should do to send a message to the public and change their habits. And we believe we should [raise the penalty] to provide a stronger deterrent effect and prevent serious problems like littering," he said.

Tse added there will be a one-month consultation period before authorities table the proposed changes to Legco next year.

The environment minister also pledged to do more to tackle illegal dumping, such as setting up more surveillance cameras in hygiene black spots.

Tse added that officials will carry out a territory-wide anti-rodent operation at the end of this year to combat rat infestation.