Protest leaders have described Monday's marches as the "final battle" against the Yingluck Shinawatra government. On that day, starting at 9.39am, all protesters will rally in front of Government House in an attempt to seize power from Ms Yingluck, said Mr Akanat, a stepson of protest leader Suthep Thaugsuban.
Mr Akanat said he believed that if a large number of people turned out, there would be a change in the government.
But if not many people join the rally that day, the PDRC would end its rally and its co-leaders would surrender to police to fight all charges in court, he added.
The spokesman insisted that the protest was not an attempt to stage a coup or tear down the constitution as critics have claimed, but a movement to bring power back to the people.
The PDRC has proposed setting up a "people's council" and "people's government" to run the country because it believes the current parliament and government no longer have the legitimacy to function.
The proposal is in line with sections 3 and 7 of the charter, he said.
Mr Suthep declared on Friday night that demonstrators would "blow the final whistle" on Monday to seize power from the Yingluck administration.
The former Democrat MP said he would not prolong the protest any longer and that Monday's outcome would make clear whether the demonstrators "win or lose".
In an attempt to counter the PDRC's "final battle" on Monday, Foreign Minister Surapong Tovichakchaikul on Saturday sent an "urgent" letter to heads of different state agencies telling them to prevent protesters from occupying their offices.
In the letter, Mr Surapong, who is in charge of the Centre for the Administration of Peace and Order (Capo), says the PDRC had violated the law by inciting unrest and instigating rebellion, which affected national stability. It actions were not accepted by the international community, he added.
"State officials have been reminded to use necessary measures to protect their respective government offices, prevent them from being occupied or surrounded by demonstrators, and continue to do their duty for the people so the country can move forward," says the letter.
Lt Gen Paradorn Pattanatabut, secretary-general of the National Security Council (NSC), said more police officers would be deployed on Monday in Bangkok areas where the Internal Security Act (ISA) is in place.
The situation would not likely escalate on Saturday and Sunday, he added.
The Bangkok protests have been going on since Nov 1, when the House of Representatives pushed through an amnesty that would have pardoned former premier Thaksin Shinawatra from a two-year prison sentence for abuse of power.
Although the bill was later rejected by the Senate, Mr Suthep has led a campaign to paralyse the government since Nov 24.
He claimed Ms Yingluck's government had lost all legitimacy when her party openly rejected a ruling by the Constitutional Court on Nov 20 that overturned a charter amendment on the composition of the Senate.
Mr Suthep said he wanted an appointed prime minister and a "People's Council" to reform the political system.
However, Pheu Thai spokesmen as well as many legal experts have said there is no provision in the current constitution for such a body.
Mr Suthep believes Section 7 of the charter could accommodate his plan by allowing for a royally appointed leader.
However, lawyers point out that His Majesty the King himself told judges three years ago that Section 7 did not give him the authority to make such an appointment.