Right-winger Edmund Stoiber has warned his supporters that his election battle in Germany will be a closely-fought affair.

Stoiber stumbles in Dusseldorf: He has struggled with response to floods

He told a rally of 10,000 supporters in Duesseldorf: "We are entering the home straight and we must mobilise all our energies."

Opinion polls put Mr Stoiber's Christian Democrat alliance (CDU/CSU) ahead, but only by as little as one point after a recent upsurge in support for Chancellor Gerhard Schroeder's Social Democrats (SPD).

If Mr Schroeder loses, he will be the first chancellor in post-war German history not to win a second term.

Jobless blow

Mr Schroeder has been hit by sluggish growth and high unemployment which, little over a year ago, appeared to pose no serious threat to him.

Gerhard Schroeder: Hoping not to make history for the wrong reasons

Mr Stoiber has been benefiting politically from the economic downturn.

And with just three weeks to election day, his job has been made easier by a recent rash of gloomy economic data and business forecasts.

Later this week, the last unemployment figures before the election are expected to show the number of jobless still above four million.

Mr Stoiber has repeatedly reminded voters of the chancellor's pledge in 1998 to cut unemployment to below three and a half million during his term in office.

Mr Stoiber, the prime minister of Bavaria, one of Germany's richest and most conservative states, told his Duesseldorf audience that under Chancellor Schroeder, the country had become Europe's economic basketcase.

Schroeder boost

But Mr Stoiber has struggled with his responses both to the recent German floods and to the possibility of an American attack on Iraq.

Frankfurt demonstrators vent their feelings against Stoiber

The chancellor's swift announcement of extra cash to pay for the flood clean-up and his vigorous opposition to any military intervention in Iraq are thought to have contributed to his party's recovery in the opinion polls.

The SPD has launched a series of risque advertisements to try to boost its success still further.

In one poster, calling for a second term for Mr Schroeder, a pair of heavily-painted lips is shown puckering for a kiss.

Underneath, the poster reads: "That was only the foreplay. The climax is still to come..."

Mr Schroeder and Mr Stoiber face their second and final TV debate on Thursday - their first was judged a tame, dry affair.