The number of jobless is seen as unlikely to fall below a 3.5 million target
The number of jobless rose 20,000 in September to 3.882 million, seasonally adjusted figures showed.
The rise, which was marginally higher than economists had forecast, took Germany's unemployment rate up 0.1 percentage points to 9.4%.
The news comes two days after Labour Office chiefs dismayed the government by admitting that, amid the slowdown in global economic growth, a target of cutting unemployment to 3.5 million looked unrealistic.
Disappointing month
The actual number of Germans without jobs fell by 45,800 to 3.74 million, Tuesday's data showed.
But, with September normally a strong month for the labour market, seasonal adjustments took the headline figure higher.
"The seasonal decline in German unemployment was noticeably smaller than in previous years," Labour Office president Bernhard Jagoda said.
The jobless total was 58,200 higher last month than in September 2000.
There was no sign yet, however, that the attacks on the US on 11 September had any serious effect on the labour market so far, Mr Jagoda added.
Jobs goal unlikely
Mr Jagoda had already warned the government of Chancellor Gerhard Schroeder that, bar unseen events, "one can certainly doubt" that the 3.5 million target would be met.
"There would have to be a seismic shift," Mr Jagoda said on Monday.
He forecast unemployment in 2001 would average nearer 3.8m than the 3.7m forecast used when drawing up benefit budgets, leaving the Labour Office short of 2bn Deutschmarks (£641m; $942m) to cover the extra claims.
During the 1998 election campaign, Mr Schroeder said the government should be judged on its ability to reduce unemployment. to 3.5m.