Germany's economy minister warned on Saturday against overblowing expectations for an economic boost from a trade deal between the United States and European Union but said the pact was needed to set high common standards for consumers.

The European Commission is trying to finalize a deal on the Transatlantic Trade and Investment Partnership (TTIP), which some experts say could generate $100 billion a year in additional economic output on both sides of the Atlantic.

It would eliminate all tariff barriers between the United States and EU members, which together account for almost half the global economy.

"I don't believe in the wondrous calculations for economic growth from (the trade deal) TTIP," said Sigmar Gabriel, also chairman of Germany's Social Democrats (SPD) which shares power with Chancellor Angela Merkel's conservatives.

"All the estimates about its impact ... give an impression of voodoo economics," Gabriel told Focus weekly.

However, Gabriel, who has long expressed reservations about some aspects of TTIP, said Europe urgently needed a deal.

"Our companies would profit because, with equal standards, they wouldn't have to go through approval procedures twice."

"Overall, Europe would profit because we could influence the standards for world trade for the coming 20 or 30 years," he said, adding without a deal, other countries, including China, would end up setting environmental and consumer standards.

Gabriel repeated the SPD's concerns about allowing U.S. mulitnationals to use so-called investor-to-state dispute settlement mechanisms to challenge Europe's food, labor and environment laws on the grounds that they restrict free trade.

The United States will not accept a deal without that.

Asked by Focus when TTIP could be finalised, Gabriel said the view in Brussels was that hopes a deal could be concluded this year were very ambitious.