UK car production was down by 43% in May to 67,754 units, but it was the smallest drop of the year.
Commercial vehicle production was down by 73.5% in May.
Paul Everitt, Society of Motor Manufacturers and Traders chief executive, said: “Prompt action by manufacturers to realign supply with demand has been painful, but was necessary.
“There is now a direct link between demand in the marketplace and production volumes. The scrappage schemes in place across Europe are now beginning to have a positive impact, although the full benefits will take a little longer to flow down to companies at all levels in the supply chain.”
Everitt said commercial vehicles had been severely affected by low “business confidence and economic uncertainty”.
He added: “Businesses across the economy are still holding back on new expenditure and will need to see better access to finance and stronger domestic demand.”