The House of Representatives and the Senate are expected to meet on July 13 to select a new prime minister, according to a source.
The source said on Tuesday the selection of the new House speaker is expected to take place on July 6, and the selection of a new prime minister is expected on July 13.
Outgoing Deputy Prime Minister Wissanu Krea-ngam explained the schedule after the Election Commission (EC) had endorsed all 500 MPs elected in the May 14 general election.
The 500 MPs-elect endorsed by the EC on Monday are from 67 parties.
"If everything goes smoothly, we can expect to get a new prime minister in the middle of July at the very earliest, and a new cabinet will take shape," government spokesman Anucha Buraphachaisri said.
"The new cabinet is then expected to take the oath of office [before His Majesty the King] by the end of July. The outgoing government will step down after the new cabinet is sworn into office," Mr Anucha said.