Lawyers for the two Myanmar migrant workers sentenced to death for the brutal murder of a pair of British backpackers in Thailand are seeking to petition the Thai king, according to a source close to the case.

Lawyers representing Zaw Lin and Wai Phyo AKA Win Zaw Tun, sentenced by Thailand’s Supreme Court to death for the Koh Tao murders, are seeking cooperation from the Myanmar Government and relatives of the two deceased victims in the UK to finalise within 60 days a petition to HM The King of Thailand.

This petition to HM The King of Thailand, to be submitted by lawyers on behalf of Zaw Lin and Wai Phyo with support from their mothers currently residing in Myanmar, shall seek the commuting of the death sentenced imposed by Samui Court in 2015 and upheld by the Thai Supreme Court this week.

The two Myanmar migrant workers, who were sentenced to death for the brutal murder of a pair of British backpackers in Thailand, lost their final appeal Thursday.

Zaw Lin and Wai Phyo AKA Win Zaw Tun were found guilty of the rape and murder of Hannah Witheridge, 23, and of killing David Miller, 24, after their battered bodies were found on a beach on the southern resort island of Koh Tao in September 2014.

Prosecutors insisted the evidence against the men from Myanmar's Rakhine state was clear, and announcing the verdict of a final appeal Thursday, Thailand's top court agreed.

Their last hope now is for a royal pardon or commutation.

During the proceedings, the defence said the evidence was not reliable as authorities mishandled DNA, did not allow independent analysis of samples and used confessions the pair said were forced.

Protests were triggered outside the Thai embassy in Myanmar's commercial capital Yangon after the original convictions.

Last year Thailand carried out its first execution since 2009, prompting criticism by rights groups who had hoped the country was moving towards abolishing the practice.

Reporting by Mizzima and AFP