Prime Minister Prayut Chan-o-cha has insisted the government remains firmly united and that it will not be subject to sabotage in a two-day general debate starting on Thursday.
Gen Prayut said there are no "moles" bent on breaking the government up.
He was responding to media questions over concerns made by some that the government may be vulnerable to a possible attack during the debate.
Although the debate will proceed without a no-confidence vote at the end of the session, the government is politically vulnerable to an attack from some of the 18 lawmakers who used to serve in the ruling Palang Pracharath Party (PPRP), according to observers.
The 18 MPs -- who have since applied for membership of the Setthakij Thai Party -- were recently expelled from the PPRP for threatening to cause trouble if the party did not overhaul the executive line-up. Originally, 21 MPs, including the group leader and former PPRP secretary-general Capt Thamanat Prompow, were expelled.
However, three of them -- Ekkarat Changlao, a list MP; Watthana Changlao, a Khon Kaen MP; and Somsak Pankasem, a Nakhon Ratchasima MP -- have since moved to the coalition Bhumjaithai Party.
On Tuesday, government spokesman Thanakorn Wangboonkongchana said Gen Prayut has instructed cabinet ministers to answer the opposition's questions during the debate.
Even though no vote will be cast in the debate, it will provide a good opportunity for the government to tell the public how it is addressing important problems, according to the spokesman.
Looking to a planned no-confidence debate likely to be tabled by the opposition in May, Mr Thanakorn said Gen Prayut was free of concerns.
Bhumjaithai Party leader Anutin Charnvirakul has denied he specifically stated that there will be at least 260 MPs backing the government in the no-confidence debate. Mr Anutin, also deputy prime minister and public health minister, stated that all he said was he would do his best to maintain stability. At least 239 MPs are required by the government to have a House majority.
PPRP leader Gen Prawit Wongsuwon reaffirmed the 18 MPs in the Thamanat faction were on the government's side although he admitted he could not control them. "No matter where they have moved to, they are still coalition members," said Gen Prawit who is also a deputy prime minister.