Thailand's total domestic car sales are expected to fall 10% year on year in 2016 to 720,000 units, the president of Toyota's Thai unit said, citing a weaker economy and a newly introduced tax.

Toyota, which commands about a third of the Thai market, also forecast its own sales there to fall this year 9.8% from 2015 to 240,000 vehicles, Kyoichi Tanada told Reuters.

"There were partial forward-buying decisions by consumers that took place during the end of 2015 before the start of the new excise tax structure," he said. "That makes us foresee the 2016 order sales in Thailand to be at a level of 720,000 units."

Thailand restructured its vehicle excise tax last year with the increase taking effect this month, the news agency noted.

Vehicle sales have been falling in Thailand since 2013, the year a government subsidy scheme for first-time buyers ended. In 2014, sales were hit by political unrest that preceded an army coup and since then, the military government has struggled to revive the export-dependant economy.

Cars, auto parts and accessories made up 12% of total exports in the year to November 2015, commerce ministry data showed, even as total exports shrank 7.42% over the same period.

In an earlier interview with Reuters, Bank of Thailand Governor Veerathai Santiprabhob stuck to the central bank's forecast of 3.5% economic growth for this year, although he said any further fall in global oil prices might lead to a revision.