In a country where memories of Gestapo misdeeds and East German police state tactics are still fresh, a call by conservatives for a constitutional amendment to do away with post-war strictures on surveillance met with outrage from other parties.

Edmund Stoiber, premier of the state of Bavaria, said that a centre-right coalition including his Christian Social Union (CSU) ought to amend the constitution to allow federal troops to patrol streets in time of emergency.

Germany's post-war constitution prohibits surveillance by the state except in rare instances. It also restricts German military deployment to strictly defensive missions and deployment abroad only as part of international peacekeeping missions.

Stoiber's call for a constitutional amendment was condemned by the Free Democrats (FDP), the centrist party most likely to form a coalition with the conservatives after a September general election.

"This is a foolhardy and populist attempt to take advantage of public fears in the aftermath of the London attacks," said FDP head Guido Westerwelle. "We will have no part of such tactics and will not condone such legislation if we are part of a coalition."

Chancellor Gerhard Schroeder's Social Democrats (SPD) also lashed out at the conservative proposal.

"The last thing we need is to adopt hasty new legislation of a far-reaching nature in a panic," said SPD Chairman Franz Muentefering.

The Greens, junior coalition partners with the SPD, also rejected Stoiber's initiative.

"The laws we have on the books already are perfectly adequate for any situation," said Foreign Minister Joschka Fischer, Greens party standard-bearer. "We reject any fear-mongering as part of our election campaign."

The standard-bearer of Germany's Christian Democrats, Angela Merkel, was to unveil her own party's election platform on Monday. The platform reportedly includes a plank calling for a constitutional amendment to widen deployment of Bundeswehr troops to include domestic operations.