Prime Minister Viktor Orbán said Hungary's say on whether Ukraine joins the EU is "decisive".
Speaking at an economic policy forum on Saturday, the prime minister said that "the Brussels plan" to allow its EU membership would ruin Europe's economy.
PM Orbán said Hungary must "make clear" its position on the associated financial burdens, and he urged the public to respond to a public survey on the subject.
Addressing the Hungarian Chamber of Commerce and Industry (MKIK) event, PM Orbán said the EU decision on Ukraine, made without Hungary's vote, "affects us" as Europe would finance the Ukrainian army, which is projected to be one million strong after the war. It would also finance the Ukrainian state rearming itself and fast-track its EU accession to offset the decision not to admit the country to NATO, he said.
This would buckle Europe's economy, so this must not be allowed to happen, he added.
PM Orbán declared that whereas Ukraine's financial programmes could be established without Hungary, its EU membership could not.
The prime minister said this matter was of such weight that it could determine Hungary's fate in the medium and long term.