The son of ousted Thai prime minister Thaksin Shinawatra has more than doubled the reward offered by police for the capture of those behind this week's deadly Bangkok bomb blast by putting up nearly US$200,000 (NZ$298,192).
Monday's attack on a religious shrine in a bustling Bangkok shopping district killed 20 people, mostly ethnic Chinese tourists from across Asia, leaving police scrambling to find the assailants and sending shock waves through the nation's vital tourism sector.
Police are convinced the attack was planned and co-ordinated by a network.
With no arrests and few clues on the identity of the main suspect in a yellow T-shirt seen leaving a backpack at the shrine moments before the fatal blast, police have offered a three million baht ($NZ125,240) reward for any information that leads to the capture of the assailant.
That offer has now been more than doubled by Panthongtae Shinawatra, the first born son of populist leader Thaksin Shinawatra.
Thaksin currently lives abroad in self-imposed exile after a corruption conviction that he insists was political.
"I have been given permission from my father to give seven million baht - two for any informant and five million for those officials who investigate and make arrests," he wrote in a Facebook post late on Friday.
"In order to swiftly regain confidence and morale among both Thais and foreigners we have to arrest the suspect as soon as possible to make everyone realise that Thailand is not (a) place where this kind of thing can happen and you get off scot free," he added.
Earlier in the week a prominent member of the Red Shirt movement loyal to Thaksin also offered a further two million baht reward - bringing the total money on offer to NZ$499474.