PDRC secretary-general Suthep Thaugsuban announced his group's firm stand at a press conference on Friday morning.
Mr Suthep repeated his explanation of why the PDRC is calling for reform, citing the government's attempts to amend the constitution and introduce a blanket amnesty law to whitewash those involved in criminal offences connected to political violence since the Sept 19, 2006 coup.
These factors had deprived the government of the legitimacy to continue to run the country's administration, he said, arguing that the country is now without a House of Representatives, and without a government for all intents and purposes.
Mr Suthep said the prime minister must accept the fact that she had lost political legitimacy. The prime minister and her cabinet must resign from their caretaker posts to create a political vacuum that would enable further proceedings to establish a people's council under the constitution, he said.
He argued that the public must reclaim power from the government and take steps to set up a people's council, which could then amend the law to guarantee clean and fair elections and effective prevention and suppression of corruption.
He said the elections must be postponed if a settlement on reform cannot be reached before Feb 2.