President Andrzej Duda on Tuesday signed the plan into effect after it passed both houses of parliament, state news agency PAP reported.
The new law allows the government to ban entry into areas at risk of migrant pressure and border incidents.
Such bans can be issued for a specific period of time and will not apply to those living, working or studying in border areas, or to people using border crossings, according to officials.
At the same time, authorities will have the right to exempt selected individuals, including journalists, from the entry ban.
The initiative comes amid turmoil on Poland's eastern border with Belarus, where thousands of migrants have gathered in recent weeks in an attempt to cross illegally into the EU from the former Soviet republic.
The months-long migrant crisis on the Polish-Belarusian border has escalated in recent weeks, with Poland, the European Union and its member states, as well as NATO and the United States accusing Belarus' strongman leader Alexander Lukashenko of orchestrating the standoff in retaliation for Western sanctions against his regime.
The new rules approved by the Polish president replace a
state of emergency that the authorities declared and then extended in the border zone in the face of the migrant pressure.
Source: IAR, PAP