As their brother faces a potential prison sentence for electoral fraud and fights to overturn his bankruptcy, two of Salim Mehajer's sisters are being asked to cough up a combined $6.2 million to cover a debt owed by one of his failed companies.

Khadijeh "Kat" Mehajer, whose 2016 nuptials rivalled those of her older brother, and Zenah Osman, the lowest-profile of the Mehajer siblings, are being pursued in the NSW Supreme Court by a demolition contractor hired by Salim Mehajer's company Sydney Project Group Pty Ltd.

Kat Mehajer, pictured at her wedding to Ibraham Sakalaki in 2016, is, jointly with her sister Zenah Osman, being pursued for $6.2 million. Credit:Andrew Murray

Administrators were appointed to the company in June last year. The Supreme Court heard last year that Sydney Project Group and a second Mehajer company, S.E.T. Services, owed almost $100 million to creditors and had just $32,000 in the bank.

The sisters claim their signatures were forged on key documents naming them as guarantors of the debt. They are seeking to engage a handwriting expert to give evidence in the dispute, the Supreme Court heard on Friday.