Mateusz Morawiecki reaffirmed Poland’s stance on the bloc’s spending plan for 2021-2027 during telephone talks with Merkel.
Morawiecki said on Facebook he had confirmed Warsaw’s “readiness to veto the new budget if we do not find a solution that is good for the entire EU, and not only for some of its members."
He added: "I told the Chancellor today that Poland expects further work to find a solution as soon as possible that would guarantee the rights of all member states and respect for treaty procedures."
A mechanism to link access to funds from Brussels with respect for the rule of law was put forward earlier this month during the German presidency of the EU.
The bloc’s new budget has to be approved unanimously by all 27 countries in the European Union, of which Poland has been a member since 2004.
Morawiecki on Thursday held talks in Budapest with his Hungarian counterpart Viktor Orban, who has also lambasted the proposed new mechanism.
After that meeting, Poland’s prime minister warned that the proposal to tie access to cash from Brussels with the rule of law could lead to the EU breaking up.
Morawiecki's conservative Law and Justice government and Hungary's Orban have both denied EU accusations of violating democratic principles and undermining the independence of their courts.
Morawiecki earlier this month told EU leaders his country opposed the use of “non-objective criteria” to decide how much cash member states receive from Brussels.