Under the decree, the contingent will also be authorised to operate in Jordan, Kuwait and Qatar, Polish state news agency PAP reported.
The mission is part of the US-led international operation Inherent Resolve, aimed at countering the Islamic State group.
Polish troops are tasked primarily with preventing terrorism and helping to build the capacity of Iraqi, Jordanian and Qatari security forces, including counterterrorism capabilities.
They provide advisory support, organise training courses and take part in NATO Mission Iraq, including training Iraqi officials and protecting advisers and military bases.
The Polish deployment in Iraq is among the country's largest and longest-running overseas missions. At its peak, the contingent numbered about 2,500 troops.
Between 2003 and 2008, Polish forces participated in the US-led operation Iraqi Freedom and subsequent stabilisation efforts following the overthrow of the Saddam Hussein regime.
Poland currently has troops deployed in about a dozen foreign missions worldwide, including NATO deployments on the alliance's eastern flank in Romania and Latvia.
Polish soldiers are also involved in stabilisation missions in the Middle East, including in Lebanon, as well as international operations in the Balkans—Kosovo and Bosnia-and-Herzegovina—and in maritime patrols in the Mediterranean Sea.
(pm/gs)
Source: PAP