Police in Thailand have been warned of bomb threats directed at a number of important landmarks in Bangkok and the surrounding area just two months after coordinated explosions targeted tourist areas across the country.

Key points: Leaked memo says attacks planned for October 20 to 25

Leaked memo says attacks planned for October 20 to 25 Targets include Bangkok's main international airport

Targets include Bangkok's main international airport Police told to be on high alert to prevent attacks

A police memo leaked to local media said an armed group was plotting up to three car bomb attacks at important landmarks in the Samut Prakan province adjoining Bangkok.

The major target of the attacks was one of the region's main transport hubs, Suvarnabhumi International Airport.

The other targets mentioned were Bhumibol Bridge, part of the 13-kilometre long ring road connecting Bangkok with its neighbouring province, and the Ancient Siam open-air museum.

The leaked documents said the attacks were planned to take place between the 20th and 25th of October this year, quoting "informants".

At least one senior police officer has confirmed the authenticity of the memo to local media, although the ABC has yet been able to independently verify the information.

Australia's Ambassador to Thailand and Ambassador for Counter-Terrorism met with the country's deputy police chief, Deputy Commissioner Srivara Ransibrahmanakul, on Monday.

In August, coordinated bomb and arson attacks hit seven provinces, killing four Thais and injuring several foreign tourists.