Niwatthamrong Bunsongphaisan, a PM's Office minister, has insisted an in-depth study is still needed to consider whether Thailand's ambitious plan to host the World Expo 2020 is worth the investment.
"We've said several times the use of taxpayers' money must be reasonable, worthwhile and beneficial to the nation," said Mr Niwatthamrong.
"If the study finds it is, then we should move ahead with the plan. If not, we should not."
He said the study will focus on the budget needed for the expo and what type of return the investment offers.
"The Thailand Convention and Exhibition Bureau (TCEB) is close to finishing its study about where the income will come from if we host the event," he said.
"Most revenue from the recent World Expo in China came from domestic visitors, 70-80% of the total, with the rest from space rentals and exhibition booth fees. We admit it will be a tough task if we run this event in the same manner and have to generate more than 10 billion baht from ticket sales."
Prime Minister Yingluck Shinawatra on Tuesday insisted the government remains committed to its bid to host the prestigious World Expo 2020 after reports that some in the administration were reluctant to continue with the effort.
She also rejected speculation that Thailand may withdraw from the contest to allow Dubai, where her brother, former prime minister Thaksin, lives in exile, to step in and host the expo.
The former Democrat government approved the TCEB's original proposal to bid with a theme "Redefine Globalisation: Balanced Life, Sustainable Living".
The Pheu Thai government approved the expo campaign last February but said the Foreign Ministry would oversee it.
That and other factors led to the resignation of Akapol Sorasuchart as TCEB president in March.
He was replaced as acting president by Thongchai Sridama, a former chairman of Thailand Privilege Card Co, operator of the moribund Thailand Elite Card.
A Kasetsart University study showed Thailand will need to invest up to 40 billion baht in facilities and buildings and another 33 billion to develop infrastructure including expanded road and rail links to serve the expo site.
Thailand is among five countries that lodged official bids for the event along with Turkey, Russia, Brazil and the UAE. The winner will be announced in November.
The expo takes place every five years and runs for six months.