The National Accountability Bureau (NAB) on Saturday filed a supplementary reference against PML-N President Shahbaz Sharif, former principal secretary to the prime minister Fawad Hasan Fawad, Lahore Development Authority (LDA) director general Ahad Khan Cheema and others in the Ashiyana-i-Iqbal housing scam.

Read more: A timeline of developments in the Ashiana housing 'scam'

Filed in an accountability court in Lahore, the supplementary reference alleges that Sharif had usurped "the powers of Board of Directors of Punjab Land Development Company (PLDC) and transferred the project of Aashiana Iqbal from PLDC to LDA."

The reference further states that Sharif, in "connivance" with Cheema, had awarded the contract to an illegible proxy which had resulted in "failure of [the] project and dishonest loss to [the] state exchequer and deprived 61,000 poor applicants from houses".

As per the reference, Sharif through his "illegal and unlawful acts while misusing his authority," caused a loss to the state exchequer amounting to Rs660 million and also led to an escalation of the project cost by approximately Rs3.39 billion.

Sharif, in the Ashiyana-i-Iqbal housing scam, is accused of cancelling the award of the project to successful bidder M/s Chaudhry Latif and Sons and instead obliging M/s Lahore Casa Developers (JV) — a proxy group of M/s Paragon City (Pvt) Limited, which the bureau claims was developed by former railways minister Khawaja Saad Rafique.