The sale of the masks has caused a political storm, leading Nikolas Loebel from the governing Christian Democrats (CDU) to resign and another conservative lawmaker to leave his party.

Prosecutors in the city of Mannheim will determine whether there is enough evidence to proceed with a full inquiry into Loebel’s actions.

The other lawmaker, Georg Nuesslein, is already being investigated by prosecutors in Munich on possible charges of bribery and corruption.

Critics from their own parties and others have accused the pair of abusing their position in public office to profit from the coronavirus crisis.

The timing of the revelations, coming days ahead of regional elections in two of Germany’s south-western states, has caused some consternation among the conservative CDU/CSU bloc in the national parliament.

The head of the CDU, Armin Laschet, has called for anyone else in the party involved in similar money-making schemes to come forward.