BANGKOK (REUTERS) - Thailand's investment agency said on Wednesday it had approved project applications worth more than 78 billion baht (S$3.08 billion) and offered tax benefits to speed up investment, as the military government seeks to help a stumbling economy.

The military seized power in May 2014 to end months of political unrest but has struggled to revive Southeast Asia's second-largest economy, with exports and domestic demand stubbornly weak.

It has stepped up infrastructure plans and accelerated approvals for private investment projects to help jolt the economy out of its rut.

The latest approvals include a 6.27 billion baht investment by Ford Motor (Thailand) to produce pick-up trucks, an 18.7 billion baht investment by Thai AirAsia X and a 6.75 billion baht investment by Nok Air, the Board of Investment (BOI) said in a statement.

The BOI has also approved tax benefits for investment applications in 2015 and 2016, with actual investment needed by the end of 2017, Hirunya Suchinai, BOI secretary-general, said in the statement.

Projects in the government's special economic zones (SEZ) will have a tax exemption for two more years or a 50 per cent tax deduction for five years, depending on existing privileges, she said.

Those outside an SEZ will get a tax exemption for one more year but together not more than eight years.

In December, the BOI replaced the previous policy by gearing its incentives towards more value-added sectors and providing special incentives to those investing in an SEZ and designated provinces.

Among the incentives are tax exemption of up to eight years and exemption of import duty on machinery or raw materials, for industries that focus on areas such as research and development, electronics design, aircraft manufacturing and production of aircraft parts.

The economy grew just 0.9 per cent last year. For 2015, the finance ministry expects growth of 3 per cent.