Victims of the 2009 Black Saturday bushfires in the Kilmore East and Kinglake districts of Victoria have until March 22 to join a class action run by lawyers Maurice Blackburn.

About 7500 people have so far signed up to the action, but it is believed the figure could reach 10,000.

The case, to be heard by Justice Jack Forrest, will begin before the deadline – on March 4 – in a specially built courtroom at the William Cooper Justice Centre in Melbourne.