Confidence among investors in Europe's largest economy Germany leaped in March, a monthly survey showed, as fears of a hard Brexit receded and progress in US-China trade talks soothed nerves.

The ZEW institute's monthly confidence index added 9.8 points for a reading of -3.6 - still in negative territory, but picking up the pace of recovery from a deep trough the indicator plumbed in October and November.

"The significant increase in economic expectations shows that important risks to the economic situation are seen as less dramatic," ZEW chief Achim Wambach said in a statement.

"A possible delay to Brexit and hope budding once again of an exit (from the EU) regulated by treaty apparently made for a more optimistic mood among the financial experts," he noted.

Meanwhile, "progress in the talks between the USA and China to end their trade war may have contributed," Wambach added.

Elsewhere in the poll of around 200 analysts and financial players, there was an even more powerful surge in economic expectations for the 19-nation eurozone, adding 14.1 points to reach -2.5.

But views of the present situation clouded over slightly for both Germany and the wider single currency bloc.

Europe's powerhouse saw slower growth in late 2018 and early 2019 as it coped with a number of one-off headwinds, including new emissions tests in the car industry and low water on the Rhine river, a vital inland freight waterway.

Government, international organisations and think-tanks have lowered their forecasts as slower global trade weighs on the export-oriented economy and capacity and labour shortages begin to bite.

Also Tuesday, the "wise men" council of economic experts lowered their expansion outlook for 2019 by 0.7 percentage points, to just 0.8 per cent.