This is the disturbing moment a policeman chased terrified kids with a handgun during bizarre school shooting training following the nursery attack in Thailand.

Footage shows the 'gunman' screaming like a crazed killer while waving the weapon and pretending to go on a rampage across the courtyard.

He knocked bins to the ground as teachers escorted children as they filed out of their classrooms at the school in Samut Sakhon province on October 27.

The bizarre exercise comes a month after a former policeman opened fire at a nursery in Nong Bua Lamphu province on October 6. Panya Khamrab, 34, killed 36 people and injured 10 others during the bloody rampage.

Policeman Phatthanont, the man holding the gun, said the training would help children to stay calm if they were caught up in an attack.

He said: 'Preparing for attacks is important. The teachers will understand what to do so that they can prevent children from being hurt.'

Other schools like the Thai Christian School in Bangkok have also conducted similar training routines following the brutal massacre.

Khamrab, who was dismissed over his methamphetamine addiction, fired a handgun and shotgun in the nursery and stabbed children inside with a machete before continuing the killing spree outside. He then killed his wife and child before shooting himself.

He later turning the gun on himself in the Uthai Sawan district.

The bloody incident is said to be the deadliest mass shooting by a single perpetrator in Thailand's history.