Speaking at an event for his Development Plus splinter group, Morawiecki told supporters the world was undergoing rapid social, economic and geopolitical upheaval.
"The world as we know it is collapsing like a house of cards," he said, adding that "history has shown its normal face again" after years in which many believed major historical change was over.
'Demography is destiny'
He described demographic decline as the country's most urgent challenge.
"Demography is destiny," Morawiecki told the crowd.
"It is not just statistics. It is a strong army, independence, a strong economy."
Without action on family policy, he warned, the Polish nation risked losing its significance and ultimately its existence within 25 to 30 years.
Morawiecki also argued that states had to either defend against migration or manage it on their own terms, rather than treating it as a solution to demographic decline.
Referring to migrant crossings into Ceuta, the Spanish enclave in North Africa, he said Europe should not simply accept migratory pressure as a consequence of EU membership.
He named energy costs as another policy priority for the new movement.
During the event, attendees have been able to enjoy barbecue food.
Organisers said a dispensation had been granted for practising Catholics, exempting them from the usual Friday obligation to abstain from meat.
The event comes amid the biggest split in Poland's main opposition Law and Justice (PiS) party in more than two decades, ahead of the 2027 parliamentary election.
Morawiecki founded the Development Plus association in April, positioning it as a more moderate faction within PiS.
Party leader Jarosław Kaczyński demanded its dissolution and ordered members to sign what Morawiecki called a "loyalty pledge" stating they did not belong to any external groupings.
Around 40 of Morawiecki's allies refused to do so by the July 23 deadline, prompting Kaczyński to declare a day later that they had effectively resigned from the party.
However, PiS's leadership referred the former prime minister and 43 others to the party's disciplinary officer rather than expelling them outright.
(ał/gs)
Source: interia.pl, PAP