While children in Singapore take a well-deserved break during the June school holidays, this girl, 11, and boy, eight, along with his father and mother toiled away in Dhaka, Bangladesh, last week. They earn less than $5 a day for carrying 1,000 bricks.

The International Labour Organisation (ILO) estimates that 168 million children are involved in child labour globally, with 45 per cent of them in the Asia-Pacific.

This year, the focus for World Day Against Child Labour, which is held every year on June 12, is on child labour and supply chains.

Businesses often rely on complicated supply chains, according to Human Rights Watch. Raw materials may be produced in multiple countries, processed or assembled into finished goods in another, and consumed in markets across the globe.

Children may be exploited at any stage of the supply chain. Millions risk sickness, injury and even death to produce these goods and services.

Existing international standards related to businesses and child labour are voluntary.

"With globalisation, supply chains have become increasingly complex, involving workers, small producers and enterprises around the world. Ending child labour in this context is everyone's business," said Ms Beate Andrees, chief of the ILO's fundamental principles and rights at work branch.