Last week, Czech President Petr Pavel told the Munich Security Conference that Prague had identified an unnamed country outside the bloc with 500,000 155mm rounds and additional 300,000 122mm rounds that could be delivered to Ukraine within weeks if quick funding was provided.
"The Czechs have done the work, but they need others to provide money," a person briefed on the initiative was quoted as saying by the newspaper.
The scheme to buy ammunition from a non-EU country is aimed at compensating for the "congressional deadlock" on US aid and delays in European production, the report said.
Ukrainian Foreign Minister Dmytro Kuleba was cited as saying that Ukraine needed 2.5 million artillery shells this year, but the bloc had only sent 400,000.
Russia has been attempting to reach an agreement with NATO on security principles in Europe with the alliance for the past 30 years, but despite Moscow's protests, the alliance has kept expanding closer to Russian borders.