The move comes after the European Union accused Minsk of orchestrating the migrant wave in retaliation for sanctions on the regime of President Alexander Lukashenko over his crackdown on opponents.
Polish lawmakers have given the go-ahead to build a controversial wall on the EU member's eastern border with Belarus, in response to an unprecedented wave of migrants, mostly from the Middle East.
The wall will cost an estimated 353 million euros ($407 million) and is planned to stretch over more than 100 km (60 miles) on the European Union's eastern border.
Polish President Andrzej Duda vowed to sign the emergency legislation within the coming days.
Thousands of migrants and refugees – mostly from the Middle East and Africa – have tried to cross the Polish border from Belarus since August.
The EU accuses Minsk of orchestrating the migrant wave in retaliation for sanctions on the regime of President Alexander Lukashenko over his crackdown on opponents.
Poland has responded to the unprecedented influx by sending thousands of soldiers to the border and implementing a state of emergency there, as well as hastily building a razor-wire fence.
Warsaw has drawn sharp criticism for its hardline approach to the crisis that has seen guards routinely push back migrants and refugees on the border.
Non-governmental organisations have warned of increasingly dangerous conditions.
Poland 'under attack'?
Poland was one of 12 member states that asked the EU to pay for border "barriers" to stop migrants from entering, but last week EU chief Ursula von der Leyen said no.
Von der Leyen, head of the EU's executive, said she told leaders at a summit in Brussels there was a long-standing position "that there will be no funding of barbed wire and walls".
Insisting that Poland is "under attack" from Belarus, nationalist Prime Minister Mateusz Morawiecki said on Thursday the wall was essential to "protect" Poland and that Warsaw had "not asked anyone for help".
A Polish state of emergency, which prevents journalists and charity workers from going near the frontier, has proved particularly controversial and the EU has called for "transparency".
The United Nations has demanded urgent action to save lives and avoid suffering on the EU-Belarus border, following the deaths of several asylum seekers.