German police on Thursday arrested a woman accused of being the ringleader of a far-right anti-lockdown group that planned to kidnap the health minister.

The plot was uncovered earlier this year, when police arrested four men accused of "preparing explosive attacks and other acts of violence" as well as plotting to abduct Health Minister Karl Lauterbach.

Investigators have now arrested a fifth suspect, named as Elisabeth R., who is thought to have been in charge of planning the operation, prosecutors said.

In January 2022 at the latest, she is accused of joining an extremist group that rejected Germany's democratic institutions and strongly opposed the government's anti-virus measures.

A central goal of the group was "triggering civil war-like conditions in Germany and thus ultimately bringing about the overthrow of the federal government and parliamentary democracy", prosecutors said on Thursday.

The group allegedly intended to achieve this by destroying power facilities to cause a nationwide blackout.

In addition, Lauterbach "was to be forcibly abducted, if necessary killing his bodyguards", the prosecutors said.

The group is said to have had an administrative branch headed by Elisabeth R., who "took a superior position and made specifications to advance and coordinate the plans".

She was also allegedly involved in efforts to recruit new members and procure weapons and explosives.

"She repeatedly demanded a quick realisation of plans and expressed concrete deadlines," the prosecutors said.

When the plot was uncovered in April, Lauterbach said he had been under police protection as a result of being targeted.

The health minister said some protesters against Covid-19 measures had become "highly dangerous" and "intent on destabilising the state and democracy".

Germany's protests against coronavirus measures at times drew tens of thousands of demonstrators, attracting a wide mix of people, including vaccine sceptics, neo-Nazis and members of the far-right AfD party.

However, anti-lockdown protests have died down this year with the easing of virus restrictions.