"We have received information that the president has decided to veto the SAFE programme bill," Tusk said at the start of a Cabinet meeting.
"I will ask the president whether this is indeed the case, as it would be an unforgivable mistake," he added.
Tusk said the government would now work on a "plan B" to ensure EU funds reach Polish businesses, saying that "hundreds of companies" were awaiting the money.
"We will find a way to secure this money for the Polish people," he said.
After the Cabinet meeting, Tusk was set to meet Nawrocki and central bank chief Adam Glapiński, alongside Defence Minister Władysław Kosiniak-Kamysz and Finance Minister Andrzej Domański, to discuss a proposed "SAFE 0%" scheme.
The prime minister said his government had requested details on how the National Bank of Poland would contribute to financing Poland's defence industry, but had so far received no response.
"All signals coming from that side suggest we are dealing with some rather suspicious operations," Tusk said, adding he intended to seek full clarity before any decisions are made.
Nawrocki and Glapiński are both allies of the right-wing opposition, which is fiercely contesting Tusk’s centrist, pro-EU policies.
The SAFE instrument provides up to EUR 150 billion in low-interest EU loans to member states for military procurement.
Poland is set to receive about EUR 44 billion, with the government saying over 80 percent would be spent within the country's defence industry, funding projects including the Eastern Shield, drone production and air defence systems.
Repayments would begin in 10 years and run until 2070.
(ał/gs)
Source: PAP