The committee was set up by the military-installed government after last September's coup which overthrew Thaksin.
The coup leaders have accused the former prime minister, who made his fortune in telecommunications, of corruption and abuse of power.
In a listing last July of Thailand's richest people, US-based Forbes magazine put Thaksin and his family in fourth place with an estimated fortune of $2.2bn.
Noppadol Pattama, Thaksin's lawyer and de facto spokesman in Thailand, said the move to freeze the accounts was "just another political decision to persecute the former prime minister".
He said Thaksin "feels that he and his wife have been unfairly and illegally treated by the AEC, and will fight and defend his innocence by bringing legal action in criminal and civil cases claiming compensation for loss of opportunity".
Noppadol said Thaksin would disclose the source of funds in every account named by the AEC.
The former prime minister was abroad at the time of the coup, and has not returned to Thailand since.
He has been warned by the military not to return until after a general election planned for December, because of fears he could destabilise the political situation.
Meanwhile English Premier League club Manchester City have said that in the wake of the asset seizure they were seeking clarification from Thaksin over his proposed $200m takeover of the football club.