Thai carmakers say sales increased during April despite the continuing political unrest in the country.

The Thai economy continues to grow and General Motors reported a 62% jump in sales to 1,879 vehicles compared with 1,162 a year earlier.

The company now plans to increase output at its Thai factory in Rayong to 76,000 vehicles and press ahead with plans to invest US$467m to upgrade facilities and build a new diesel engine plant.

Toyota , number one in the Thai market, increased deliveries 43% to 92,000 and Isuzu ’s sales jumped 44% to 46,071.

All three companies have reported increases in Thailand in the in the first four months of this year, while the country’s vehicles production doubled in March to a record as the global economic recovery boosted domestic and overseas demand.

The Thai economy is forecast to grow this year even as clashes between the government and protesters may slow the pace according to the finance ministry.

Thailand’s vehicle output in March rose 129% from a year earlier to 150,119 vehicles, the Automotive Industry Club trade group said.

The political unrest is a concern, however.

Ray Young, GM’s vice president of international operations said: “We are monitoring the situation in Thailand, but we remain optimistic. Our business and expansion plans will continue in Thailand without delays. The nation “will remain the leading automotive market in the Asean region.”