BANGKOK (Reuters) - The Thai government's flagship 500 billion baht ($13.8 billion) "digital wallet" handout scheme will spur job creation and stimulate underdeveloped provinces and regions, Prime Minister Srettha Thavisin said on Thursday.

Some minor changes to the policy reflect public opinion, he said in a speech to parliament, adding the government planned to announce all the details of the policy on July 24.

"The capital injection will help spur manufacturing and create jobs," Srettha told lawmakers.

The scheme, which would see about 50 million Thais receive 10,000 baht each to spend locally within six months, is slated to start in the fourth quarter but the government has struggled to find sources of funding.

Srettha did not mention the total budget cost of the policy in his speech. On Wednesday, a deputy finance minister said that based on past experience there might be a take-up rate of about 90%, which meant the scheme could cost around 450 billion baht.

Two former central bank governors and economists have criticised the plan as fiscally irresponsible, but the government has rejected those arguments.

"You are able to diagnose the issues, but the solution is unclear," said opposition lawmaker Sirikanya Tansakul in response to the Prime Minister's speech.

($1 = 36.2500 baht)