The latest road safety crackdown was launched in an order issued to all 88 police stations in Bangkok.
Traffic division and all other officers at the police stations were directed by deputy Metropolitan Police Bureau chief Adul Narongsak on Monday to take action against all motorists seen chatting on mobile phones without using a hands-free device.
The Land Traffice Act bans drivers using mobile phones unless they use a hands-free device or a speaker phone, because it distracts their attention and they do not have proper control their vehicles. Offenders face a fine of 400 to 1,000 baht.
Police strictly enforced the law when it was revised to add the mobile phone ban and enforced in 2008, but it was later relaxed.
Pol Maj Gen Narongsak said this time police will take serious action, fining violators on the spot or taking pictures of a driver and the vehicle's registration plate and sending them traffic infringement notice, which they will have to pay.