Despite the name change the Puea Thai Party remain loyal to Thaksin Shinawatra, the exiled former prime minister, ousted in a military coup in 2006.
The PPP was leading a coalition which is still ruling the country in a caretaker capacity.
They say that they will not reliniquish power easily and has said that there is the possibilty of renewed street protests.
However, anti-government protesters whose demonstrations had shut down Bangkok's two airports, maiming the country's tourist industry, say that they will rally if any new government is too close to Thaksin.
On Saturday, the Democrat Party gained the support of four small parties that were part of the coalition with Thaksin's allies formed after elections in December last year.
Abhisit Vejjajiva, the Democrat Party leader, could become prime minister if his party mamages to form a ruling coalition.
"Parties are seeking support. Puea Thai party still sticks together," Somchai Phetprasert, a parliamentarian with Puea Thai, said.
"Most of MPs will be with Puea Thai. [The opposition] announcement was not clear -- the political direction will be clearer in next couple of days."
The different sides will be vying for support from smaller parties and factions in their attempts to form a governmnet.
The Democrat Party say that it wants to restore stability in Thailand after six months of protests by the People's Alliance for Democracy (PAD), who say that the PPP is running the country for Thaksin while he is in exile.
Thaksin was convicted in absentia in October to two years in jail for corruption.
The PAD's protests climaxed late last month with the sit-ins at Bangkok's airports.
Tens of thousands of tourists remain stranded due to the closures.