David Cameron says business deals worth more than £750m ($1.2bn) will be made during his tour of South East Asia.
Mr Cameron, who has arrived in Indonesia, is accompanied by 31 British business leaders on the trade mission.
The UK prime minister says he wants to forge links with the area’s rapidly growing markets for British goods and services during his four-day trip.
He will also discuss the threat of the self-styled Islamic State group and climate change during his trip.