Ousted premier Thaksin Shinawatra is understood to have turned to a pre-recorded message aimed at hyping up tens of thousands of his supporters expected to show up today at Bangkok's Rajamangala Stadium.
Previously, Thaksin planned to phone in from overseas for a live speech to his audience. However, this was reportedly cancelled out of fear of worsening the political situation.
Government sources said Thaksin arrived in Hong Kong yesterday, where he will record an eight-minute message for today's gathering of his supporters.
Thaksin's message is expected to be softer than his previous remarks, playing the middle ground in the ongoing political conflict with emphasis on national reconciliation and loyalty to the monarchy.
Previously, the military voiced strong opposition to his plan for a live address.
Chaowarin Latthasaksiri, a government MP, said yesterday that Thaksin was in Dubai prior to his arrival in Hong Kong.
Meanwhile, both anti- and pro-government groups started to reach Bangkok from various parts of the country.
The Phichit chapter of the People's Alliance for Democracy said PAD-led crowds from the North would surge at Government House in order to counter the pro-government rally at Rajamangala Stadium.
The PAD's Nakhon Ratchasima chapter has also stepped up its mobilisation of people from the Northeast to travel to the capital.
Organisers of the pro-government rally have started dispatching convoys to transport their people from the Northeast, seen as the stronghold of the main coalition partner, the People Power Party.
Rajamangala Stadium can accommodate 70,000 people and today's crowd might surge to around 100,000.
Army chief General Anupong Paochinda has ordered close monitoring of the situation with the aim of preventing the opposing factions from clashing, said Army spokesman Colonel Sansern Kaewkamnoed.
Sansern said soldiers were on the standby to assist the police in keeping the peace.
Despite reports to the contrary, People Power Party MP and event organiser Jatuporn Prompan said Thaksin's phone-in plans remained unchanged and he would address his supporters at 8pm today.
"Thaksin is free to speak out and will not be restricted by topics and time constraints," Jatuporn said.
He said he anticipated Thaksin would begin his speech by rousing the crowd with an anti-coup message and sharing his thoughts on global economic volatility, before moving on to any topic of his choice.
He said he did not know from which location Thaksin would make his telephone call. There has been speculation that the ousted premier flew from London to Hong Kong via Dubai for the phone-in session.
The rally - billed as the mobile event of the "Today's Truth" talk show aired by NBT Channel - will begin at 3pm and is expected to conclude around 10pm. Key speakers are scheduled to address the crowds from 5.30pm as a forerunner to Thaksin's phone-in, which is billed as the main attraction.
The event will be taped and highlights will be broadcast during the NBT talk show on week nights.