As investigations on the Bangkok explosion are underway, two men identified as suspects in the Bangkok bombing have handed themselves in to police, insisting they are tour guides, authorities say.

The pair was seen in security camera footage shortly before Monday's blast at the Erawan Shrine, leading to the death of 20 people and several casualties.

The men, in red and white T-shirts, rose from a bench shortly before the main suspect, in yellow, sat down and left behind his backpack.

Officers are currently interrogating the pair.

The police had said that at least 10 people were suspected of involvement in the attack, and that the prime suspect was foreign.