Gulf Energy Development and Siam Cement Group (SCG) are urging the government to improve Thai companies so they can stand out in the global business arena.
The two SET-listed firms operate businesses across Asia-Pacific and Europe, and they agree that authorities must work to update regulations that facilitate investment for Thais overseas, helping them to become leading multinational firms.
Gulf, Thailand's biggest private power producer by market value, set up a firm in Singapore to expand its business after having to deal with complicated rules while raising funds in Thailand.
"Financial costs in Singapore, especially those related to international business transactions, are much lower than those in Thailand," said Sarath Ratanavadi, chief executive of Gulf.
Mr Sarath wants the government to remove unnecessary regulations to fuel the growth of Thai companies, part of efforts to help Thailand escape the middle-income trap.
Over the past few years, Gulf has diversified into new businesses. Earlier this year, the company signed a deal to invest in a digital asset exchange service from US-based Binance through seed funding.
Binance is the world's largest cryptocurrency exchange by trading volume.
Mr Roongrote says the government needs to attract foreign talent.
Last year, Gulf synergised its business with Advanced Info Service Plc (AIS), the country's biggest mobile operator, to pave the way for digital infrastructure development, which it said will become an economic core in the future.
Gulf, which earlier acquired InTouch Holdings, now holds a 42% share in InTouch Holdings Plc, which controls a 40% share in AIS.
SCG, Thailand's largest cement maker and industrial conglomerate, also aims to diversify into energy, automation, and businesses related to bio-, circular and green economic development.
Roongrote Rangsiyopash, president and chief executive of SCG, suggested the government carry out plans to attract more talent with expertise across various fields to work in Thailand because they will be key in creating innovation, eventually helping Thai companies become leaders in the global market.
Echoing Mr Roongrote, Mr Sarath said manpower will drive business and economic growth, and Thai authorities must ensure regulations are designed to support their lives in the country.
Mr Sarath said Thailand also needs to improve its competitiveness to attract more foreign investments.
Vietnam and Indonesia now seem to be foreign investors' first choices when they expand their businesses into Asean, he said.