"Given the slowdown in demand we are seeing now, a $1 billion reduction in exports this year is not unreasonable," he told Reuters. "Our projection is it could be five to six more months before we see a recovery in global demand."
Shipments to the Unites States, the country's biggest buyer, dropped by 22% to $470 million in the first quarter.
Exports to the European Union fell 13% to $344 million while first-quarter exports to the United Kingdom were down 10% to $167.7 million, according to the latest JAAF data.
A steep 66% power tariff hike in February has also hit Sri Lanka's competitiveness, Lawrence added.
However, the industry is not expecting significant job losses from the downturn but small and medium companies could see difficulties as the sector adapts to deal with a slowdown in orders.
The island's apparel sector has about 300,000 employees, most of whom are women. (Reporting by Uditha Jayasinghe; Editing by Raju Gopalakrishnan)