French Finance Minister Bruno Le Maire said he would try to convince sceptical nations to agree on a corporate tax deal at a meeting in Luxembourg on Friday, but he acknowledged that reaching an agreement was "very difficult".
An EU deal had been expected on Friday after Poland dropped its opposition to setting a minimum corporate tax of 15% on big multinationals, officials said, but Hungary emerged as a last-minute hurdle.
The EU talks are meant to turn into law a global reform of corporate taxation, which was agreed last October by nearly 140 countries.
Le Maire made the tax deal a key goal of the six-month French presidency of the EU, which ends in two weeks, but recognised that political hurdles had emerged.
"We still hope to reach a deal today, but it is very difficult," Le Maire told reporters before the meeting of finance ministers.
He declined to make direct comments about Hungary's position, but he underlined that all technical issues had been long solved, implying the stalemate was caused by political reasons.
Poland and Hungary have been at odds with the European Commission, which has held up their receipt of COVID-19 recovery fund money over questions about their stance on the rule of law and other EU values.
Earlier in June the Commission approved payments to Poland, whereas EU recovery funds for Hungary remain frozen.
The overhaul set global minimum corporate tax of 15% on big multinationals and gave other countries a bigger share of the tax take on the earnings of big U.S. digital groups such as Apple Inc and Alphabet Inc's Google.
The reform was originally intended to be applied in 2023, but its implementation has now been pushed back to 2024 .
The Biden administration is also struggling to pass legislation that would implement the global minimum tax deal.
