It is demanding €600,000 damages from his wife and two daughters in connection with the so-called “Birnbacher scandal” - a kickback scheme which milked money from the sale of state bank Hypo Alpe Adria to the German bank BayernLB in 2007.
Haider's tax adviser Dietrich Birnbacher drew up a plan for the bank sale and funnelled back money to Haider and other local politicians which they allegedly used to finance their parties.
Birnbacher later confessed. Austria nationalized Hypo Alpe Adria in 2009 to avoid a collapse of the then BayernLB-owned bank that would have sent shock waves through central and eastern Europe.
According to a report in the Kleine Zeitung newspaper, Carinthia will seek €200,000 in damages from each of Haider's heirs - his wife Claudia and daughters Cornelia and Ulrike.
A civil court now needs to rule if Carinthia's holding company can raise such a lawsuit against the heirs.
Carinthian BZÖ MP Willi Korak said the move was "incomprehensible" and "politically motivated", and that there was no proof that any political parties had got rich from the Birnbacher scandal.
Carinthia is on the line for an unpayable €10.2 billion for guarantees on Hypo bank loans - more than four times the annual state budget - and faces possible bankruptcy.