Polish prime minister designate Donald Tusk is due to be be nominated as head of the new government this afternoon.
Mr Tusk's centre-right Civic Platform won a parliamentary election on October 21st, ousting the conservative Law and Justice party headed by Prime Minister Jaroslaw Kaczynski.
The handover of power to Civic Platform and its likely junior coalition partner, the centrist Polish Peasants' Party, began on Monday when Mr Kaczynski presented his resignation.
Mr Tusk has said he will announce his cabinet soon after the nomination.
Mr Kaczynski and his twin brother Lech, Poland's president, have expressed bitterness at losing the election despite having presided over Poland's fastest economic growth in a decade.
Some conservative party members have suggested the president may try to block key bills presented by the new government.