Ms Yingluck was responding to questions about a rumour the caretaker government would allow the military to stage a coup to end the political conflict and that there would be an election one year after that.
The prime minister said she, as the defence minister, believed the commanders of all armed forces would consider the long-term consequences and heed His Majesty the King's advice.
Tthe best way out was for all sides to meet for talks, she said.
On the Jan 13 shutdown of Bangkok by the People's Democratic Reform Committee, Ms Yingluck said the government and security agencies would strictly adhere to a peacekeeping role, to prevent clashes between the authorities and the protesters.
No weapons would be allowed into protest areas, she said.
Army chief Gen Prayuth Chan-ocha, when asked to comment on the coup rumour, said people should not be afraid of what was still invisible. He once again refused to confirm or deny the possibility of another coup.