Chavanond Intarakomalyasut said the party plans to boycott talks scheduled for Monday on a proposed amnesty bill, the Bangkok Post reported. The bill was introduced Thursday with 42 sponsors from the Pheu Thai party.
Four other bills have been introduced.
Chavamond accused supporters of the bill of hoping to rehabilitate Thaksin Shinawatra, the former prime minister ousted by a military coup and now living in exile. Shinawatra's sister, Yingluck, is now prime minister.
Deputy House Speaker Charoen Chankomol said he has invited a broad range of groups to the discussion with the goal of healing Thailand's divisions.
The period after Thaksin's ouster in 2006 was one of great political instability with a number of political groups usually known by their shirt colors demonstrating in Bangkok. There were hundreds of arrests.