Lawmakers will most likely ask voters whether senators should be allowed to vote on a prime minister alongside MPs as the additional question at the Aug 7 referendum.
The National Legislative Assembly (NLA), the body that has the final say about the question, shared the view of the National Reform Steering Assembly, which agreed on the same question last week.
The question suggested by the NRSA is: "Do you agree to allow the first batch of senators after the election to jointly vote with MPs in choosing a prime minister?"
"We've given it the most weight now since we believe during the five-year transition period, there should be a mechanism to stabilise politics," said Witawad Boonyasatid, an NLA member.
"We have to admit the situation is not stable. Bowls are handed out by Thaksin Shinawatra to incite people. There may be unrest all over again after the election," Mr Witawad said.
He explained the privilege was only for five years and the senators would not have the power to launch no-confidence debates, just to screen a prime minister.
The NLA will most certainly vote for the question on Thursday, he said.
His view was shared by Kittisak Rattanavaraha, another NLA member, who added other questions proposed such as the use of two ballots or a reconciliation government had lost steam.
Critics said adding another question at the referendum would come at the expense of the charter, which would lose its focus.
Others have slammed the idea is undemocratic since the first batch of senators after the election will be handpicked by the junta. Even a party wins a majority vote in the House (250 or more), it cannot be sure its candidate would be the prime minister since he or she must have the blessing of the senators.
"It is against principles. The appointed 250 persons should not be allowed to overrule people's will," Abhisit Vejjajiva, leader of the Democract Party said on Saturday.
