During a ceremony at the presidential palace in the capital Warsaw, Jaroslaw Kaczynski pledged to work to cleanse Poland of what he considers the corruption that has flourished for the past 15 years.

He said his future Cabinet would continue the pro-social welfare policies of outgoing Prime Minister Kazimierz Marcinkiewicz's government.

"...... I would like to stress that the task undertaken by Mr Marcinkiewicz and his cabinet will be continued. We will do all that we can."

Marcinkiewicz officially stepped down on Monday amid reports of disagreements over economic policies between him and Jaroslaw Kaczynski, who is widely regarded as the power behind the scenes of the outgoing government.

Marcinkiewicz is set to become the Law and Justice party's candidate for the new mayor of Warsaw.

The new prime minister now has 14 days to form his Cabinet, and then another two weeks to win a vote of confidence from Parliament.