“Time is short and there is much to do,” Persson said in a statement.
“There is a need to empower senior negotiators to bring the negotiations back on course,” he said.
Persson issued the statement as a row over farm import duties is threatening to derail the talks, which are due to conclude with a WTO ministerial meeting in Hong Kong in December. At the centre of the dispute is a difference between EU and US ways of processing trade data used in duty calculations.
Persson also confirmed that OECD ministers believe growth in their economies will regain momentum later this year and will become more balanced. But he warned that high oil prices and global imbalances pose a risk to the economic outlook across the OECD.
The ministers see oil prices as “a prominent” risk, he said, adding that “enduring external and internal imbalances also overshadow the outlook in the form of widening current account gaps, large fiscal deficits and possibly stretched valuations in some asset markets”.
He cautioned: “While the imbalances may well unwind smoothly, including via some exchange rate adjustments, some turbulence cannot be ruled out.”
Before Wednesday’s meeting Persson had told reporters that he was not expecting much progress but remained optimistic that the farm import duties row will be defused.
“We can’t afford to fail,” he said.
“That’s why I’m optimistic. And, to be honest, we always experience a crisis like this before we come to the final negotiation. I’m not surprised. I think we’ll do it,” he said.
He dismissed suggestions that EU sensitivities over the upcoming French referendum are behind the dispute.
“There is always a referendum around the corner or an election but I don’t think it plays such an important role just now,” he said.