Thailand's investment agency has approved applications for projects worth 79.2 billion baht ($2.4 billion) mainly in the automobile industry, it said on Tuesday.

The world's top car makers use Thailand as a regional base for vehicle production and exports.

The approved projects include investment of about 10.4 billion baht on eco-cars, or fuel-efficient cars, by Toyota Motor, and an investment of 8.4 billion baht by Suzuki Motor, the Board of Investment (BOI) said in a statement.

Honda's Thai unit will invest about 8.2 billion baht, and a joint venture of China's SAIC Motor Corp and Thailand's Charoen Pokphand Group plans an investment of 7.6 billion baht for eco-car production, it added.

Also approved were a 3.1-billion-baht production expansion plan by Nissan Motor, and an ethylene production project by PTT Global Chemical worth 9.8 billion baht, the agency said.

The authorities have accelerated the approval process after delays caused by months of political unrest that prompted a military coup in May.