He says there are thought to be some 2-3,000 die-hard protesters who have barricaded themselves in, and they are hugely outnumbered.
He says this appears to be a final push to end the current crisis, but it is not yet clear how much of a fight protesters are prepared to put up.
Earlier, some in the camp told the BBC they were prepared to "fight to the death".
Mr Abhisit has said he will not negotiate with Mr Thaksin and that the country was facing a "do-or-die" moment for the rule of law.
He told Reuters: "I do listen to the concerns of some people who have joined the 'red shirts' in terms of democratic developments."
"In particular, if they are not satisfied with the constitution, if they think there may be some injustice in the system, I am happy to address those," he said.
But he said that dissolving parliament and calling elections could lead to further instability.
The prime minister confirmed that two local people had been killed in the violence.
Thaksin on protests in Thailand
But there have been unsubstantiated claims from some of the protesters that more that two people were killed in yesterday's fighting.
"Many 'red shirts' have been killed," said Wannee Sathit, a protester speaking from inside the camp near Government House.
"The army has taken the dead bodies away."
In a BBC interview on Monday, the ousted Mr Thaksin said the situation in Thailand was one of "very brutal suppression".
He called for a "peaceful revolution", saying the protesters "come with bare hands".
"They come with peace, they are asking for a true democracy for all," he said.
But our correspondent says the red shirts have largely lost popular support after the violence and destruction of Monday and are greatly outnumbered by the military with little chance of keeping the protests going.
Under the current state of emergency, gatherings of more than five people can be banned, media reports can be censored and the army can be deployed to help police maintain order.
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