In baby-blue caps and yellow scout scarves, an army of royal volunteers is sprucing up Thailand before this weekend's coronation -- a projection of unity and loyalty to the unassailable crown in a divided kingdom that remains locked in political crisis.

Labour Minister Pol General Adul Sangsingkeo has urged migrant workers from Cambodia, Myanmar and Laos to undergo nationality verification and official registration to work legally in Thailand before the One Stop Service (OSS) centres close on June 30.