While in Berlin, the Polish prime minister will also speak to Olaf Scholz, who is set to take over from Merkel as head of government next month, public broadcaster Polish Radio's IAR news agency reported.
Then, on Friday, Morawiecki will visit London for talks with British Prime Minister Boris Johnson as Poland continues its diplomatic drive to resolve the migrant crisis, according to officials.
On Wednesday, the Polish prime minister held talks with French President Emmanuel Macron in Paris and the Slovenian head of government, Janez Janša, in Ljubljana.
On Tuesday, Morawiecki attended a summit of the regional Visegrad Group in Hungary and also paid a visit to Croatia, while on Sunday he toured the Baltic states of Lithuania, Latvia and Estonia.
Visit to Slovenia
With Slovenia currently presiding over the European Union, Morawiecki said his Wednesday's talks with Janša had been "very important in forging a European community that is secure, just and bound by solidarity," the IAR news agency reported.
As he met reporters alongside the Slovenian leader, Morawiecki said Poland "doesn't want a conflict" with Belarus, but would step up sanctions if migrant pressure did not ease off.
"We are prepared to close border crossings, to suspend trade, although we don't want to do it, we are working to de-escalate the situation," he added.
Meanwhile, Janša expressed solidarity with Poland and congratulated Warsaw on "firm and bold action" to stem "a wave of illegal migration."
Call for unity
Commenting on his talks with the French and Slovenian leaders in a Facebook post on Wednesday evening, Morawiecki said: "We agree that many European countries are feeling the tightening of the Russian noose when it comes to energy, as well as heightened propaganda efforts and hacker attacks, designed to disrupt our solidarity."
"We won't let that happen," he added.
"The series of crises affecting us is a test for Europe," he also said in his post. "It's a time when we, the European Union, have to be united and focus on things that matter the most."
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.
(pm/gs)
Source: IAR, PAP