The officials said Wan Noor would hold a meeting of Senate whips and representatives of the Pheu Thai-led coalition and those outside the bloc at 10am.
The meeting was called after the Constitutional Court tacitly gave the go-ahead for the next PM vote by rejecting a petition of the ombudsmen to invalidate a parliamentary resolution that blocked the renomination of Move Forward PM candidate Pita Limjaroenrat.
Somchai Sawaengkarn, an adviser to the Senate whips, said Wan Noor had earlier discussed with deputy Senate speaker Supachai Somcharoen and agreed on on August 22 as the tentative date for the PM vote.
According to Somchai, Supachai advised Wan Noor to inform the Senate whips to alert senators of the PM election date as soon as possible