"We have managed to form a coalition with more than half the seats in the parliament," Kuthep said.
Thaksin's allies in the PPP came out on top in the country's first election since he was removed from office by the bloodless military coup in September last year.
The PPP won 233 seats in the 480-seat legislature while the anti-Thaksin Democrat Party won only 165 seats.
The PPP campaign had focused heavily on bringing Thaksin back to the country where he remains highly popular especially with the rural masses.
Last week, Thaksin said he was considering coming back by April, but the Thai authorities said he will be arrested on corruption and fraud charges if he returns from his self-imposed exile.