He said that with 314 functioning House seats, there is no chance of a reshuffle.
Speaking before attending the weekly Cabinet meeting on Tuesday, Phumtham insisted that the Democrat Party electing a new chief was in no way linked to the government.
The Democrat Party ended months of uncertainty on Saturday by electing acting leader Chalermchai Sri-on as its new chief.
The previous two attempts to elect a leader had failed due to a factional boycott.
Phumtham, who also holds the Commerce portfolio, said there are no plans to add more parties to the coalition, as the 314 seats in the Lower House were sufficient.
He added that the Cabinet was collaborating well in harmony and was primarily focused on its work.
Political observers believe that under Chalermchai, the Democrats may align more closely with its arch-foe Pheu Thai.
