The ban follows a week-long probe of Schering's Brazilian operations, which produced at least 13 million placebo birth control pills that later entered the market, the ministry said.

But it warned that millions more may have found their way to pharmacies because Schering could not account for the destruction of some 35 million flour-based pills, which were manufactured to test a new packaging machine.

"This is absurd," a ministry spokeswoman said. "Their accounting procedures simply do not comply with basic safety standards, so how do we know all of their products are safe?"

Brazilian authorities will inspect Schering's plant again on July 9, when they could lift the ban, the ministry said. The incident took another twist Friday when Brazil's foreign ministry summoned an attache from the GermanEmbassy to express "surprise and displeasure" after Schering complained of "harsh accusations" made by Brazilian health minister Jose Serra. In a statement issued Wednesday, Schering also said the Brazilian media had over-reacted when covering the story.

"Although the German government is not involved in this regrettable episode, the Brazilian government must express its rejection of the unacceptable attitude of Schering's headquarters in Berlin," the foreign ministry said in a counter statement.

The scandal erupted roughly two weeks ago when a woman complained on local television that she became pregnant after taking bogus contraceptives sold under Schering's Microvlar brand. Schering's Latin America marketing director Theodorus CM Van Der Loo said the woman had previously contacted the company on June 1, but the Brazilian subsidiary waited until after the programme ran to approach the police or the public. "We thought this was an isolated incident and we wanted to look at it internally," Van Der Loosaid. "We have to admit we made some mistakes."

In Frankfurt, Schering AG has insisted the placebo pills were given to another company for destruction, adhering to correct company procedure.

Brazil's justice ministry fined Schering $2.5 million on Tuesday for selling fake contraceptives, a charge the company strongly denies.

It was the maximum amount possible under Brazil's Consumer Defence Code and the largest fine ever handed down to one company.