Speaking at the "Poland Future Summit" event in Warsaw, Nawrocki argued that migration had failed to solve population challenges in Western Europe.
He said both Poland and the rest of Europe were facing a demographic crisis marked by declining birth rates and an inability to replace aging generations.
He said Poland recorded about 160,000 more deaths than births last year, a population loss equivalent to a mid-sized city.
"We must make every effort to stop the worsening demographic problem in Poland and across Europe," Nawrocki said, calling for cooperation among policymakers, businesses and civil society.
The president warned that demographic decline could have serious consequences for economic growth and national security.
Nawrocki, a conservative allied with the opposition, said one of his first legislative initiatives after taking office last August was a proposal to exempt parents with two or more children from personal income tax.
He expressed regret that the measure had not yet been approved by parliament and said he hoped lawmakers would adopt it soon.
He also welcomed what he described as broad political support for raising the threshold at which higher income tax rates apply, saying such measures could help create conditions favourable to larger families.
"Given the consensus in parliament, I do not understand why the government is not taking up this initiative," he said, in a familiar swipe at Prime Minister Donald Tusk's centrist Cabinet.
'Ghettoisation, integration challenges, social unrest'
Nawrocki argued that many Western European countries had responded to demographic decline by turning to immigration, a policy he said had failed to resolve underlying population problems.
"When a demographic crisis emerges, migration pressure follows," he said.
"Migration pressure in Western Europe has not solved the problem but has brought ghettoisation, integration challenges and social unrest," he added.
"That is not and will not be the Polish path," Nawrocki told the gathering. "We will not address the demographic crisis by yielding to migration pressure."
Instead, he said, Poland should focus on supporting families and creating legal and economic conditions that encourage people to have children.
'Crisis of masculinity'
The president also called on businesses to help employees balance work and family life, while warning against excessive regulation that could hamper economic activity.
He further argued that cultural changes and growing individualism had contributed to falling birth rates across Europe and said the continent was also facing what he described as a "crisis of masculinity."
Nawrocki concluded his remarks by extending Father's Day wishes ahead of the holiday, which is observed in Poland on Tuesday.
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Sources: IAR, PAP