Twenty thousand police officers are to be deployed across the capital for the New Year countdown, especially at four major spots where revellers will gather in large numbers.

The four countdown venues are CentralWorld, Khao San Road, Asiatique and the Crystal Design Centre, according to Pol Maj Gen Montri Yimyaem, deputy chief of the Metropolitan Police Bureau.

CentralWorld, where a bomb went off during the 2006 New Year countdown, is expected to be the most crowded venue with at least 125,000 revellers, some 25,000 more than last year.

Pol Maj Gen Montri said the 20,000 security personnel will guard the four countdown venues as well as 144 temples where Buddhist prayers are planned to be held to ring in the New Year.

Despite tight security being put in place, Tourism and Sports Minister Weerasak Kowsurat asked the public on Monday to keep a look out for any suspicious behaviour and report to the authorities. He asked revellers to capture any such footage on their smartphones for potential use as evidence.

He added that 115 security checkpoints will be set up across the capital.

Around the country, 50,000 military personnel, police and civilian volunteers will work together to beef up security and conduct joint patrols, according to deputy national police chief Pol Gen Chalermkiat Sriworakhan.

Police will use infrared cameras to capture images of illegal activities in the dark.

Elsewhere, police have already stepped up security patrols.

In Phuket, police since Friday have seized weapons after a series of raids on 20 locations during which 33 suspects were detained.

Of the detained suspects, three had arrest warrants out for them already and one was suspected to have entered Thailand illegally.

Phuket police said they will continue conducting their raids until Jan 5.

Police across the country also plan to enforce traffic laws strictly. Police checkpoints will target not only drink drivers but also motorcyclists who fail to wear crash helmets.

In Phetchabun province, Anon Chuealek, chief of Lom Kao district office, warned people planning on visiting Phu Thap Boek, a popular hilltop tourist attraction, to brace for bad traffic on the road leading to the destination.

Each day during the New Year holiday period, at least 15,000 visitors are expected at Phu Thap Boek, which will inevitably result in severe traffic congestion on the small road leading up the mountain, he said. In a bid to provide live traffic updates for motorists, drones will be used to capture images of road congestion, he said.

In Nakhon Ratchasima on Monday, more than 500 people began to campaign to raise public awareness about the importance of reducing the volume of rubbish and consumption of energy, both of which tend to surge during the New Year celebrations.