Berlin  - German investor confidence posted its second unexpected rise in two months Tuesday, with analysts attributing this to lower energy prices and a stronger dollar providing a boost to exports from the eurozone.

Drawn up by the Mannheim-based Centre for European Economic Research, the ZEW September index rose to minus 41.1 from minus 55.5 points in August.

The ZEW appended a special note on the fall-out from the collapse of US bank Lehman Brothers, saying that a separate analysis of 31 answers that came in after the bankruptcy showed that the economic expectations for Germany had not deteriorated.

The ZEW said there were two essential reasons for the recovery of expectations: "On the one hand, the ongoing decline of the oil price eases the burden on consumers and firms. On the other hand, the tendency of the euro in the past weeks to depreciate against the US dollar benefits German exporters."

ZEW President Wolfgang Franz added: "Due to the declining oil price the inflationary pressure is decreasing. This should improve the perspectives for German consumption."

Commerzbank economist Matthias Rubisch was dismissive of the indicator in the light of this week's events on global stock markets, describing the improvement in investor confidence as "broadly inexplicable."

"Given the renewed deterioration in the finance crisis this week, the results are probably faulty," he said in a written analysis, predicting a lengthy economic downturn.

Two German economic research institutes revised downwards their optimistic forecasts on economic growth in Europe's largest economy in forecasts published Tuesday.

The Essen-based RWI said it expected gross domestic product growth to come in at 1.7 per cent, down from a previous prediction of 2.2 per cent.

Hamburg's HWWI cut its forecast to 1.9 per cent from 2.2 per cent.

The forecasts are in line with those of the German Finance Ministry, which is predicting growth of 1.7 per cent this year.

The institutes also cut their forecasts for next year, the RWI more than halving its growth forecast to 0.8 per cent, while the HWWI cut its prediction to 1.0 per cent from 1.1 per cent previously.

The Finance Ministry has put 2009 GDP growth at 1.2 per cent in an estimate it describes as "conservative."

The ministry's medium-term plan foresees a balanced federal budget by 2011, a goal repeated by Finance Minister Peer Steinbrueck Tuesday as he addressed the lower house of parliament on the first day of the 2009 budget reading.

As it approached, this target was becoming increasingly "realistic," Steinbrueck said.

In his speech to the Bundestag, the finance minister cautioned against "overdramatizing" the fall-out from the global financial crisis.

"Although this financial market crisis without a doubt poses the largest threat to the German economy, I regard the possible effects on us as limited," Steinbrueck said. (dpa)