Pakistan Muslim League-Nawaz (PML-N) leader Khawaja Saad Rafique and his brother Khawaja Salman Rafique produced before accountability court in Paragon Housing reference.
The court extended the judicial remand of brothers till 11th February.
Strict security arrangements made to avoid any untoward incident.
NAB Lahore had approved filing of a reference against the Khawaja brothers and Nadeem Zia for the alleged corruption.
Qaiser Amin Butt, the main accused in the case, also included in the inquiry initiated by the NAB, and arrested in November last year.
Later, he agreed to turn approver against the Khawaja brothers and Zia.
On December 11, 2018, Khawaja brothers detained by the accountability watchdog after the Lahore High Court (LHC) rejected their bail plea.