The accountability watchdog alleged that the leader was involved in corruption by providing contracts on high rates to unqualified companies of his friends, reports say.
Shahbaz, 67, is the younger brother of ousted prime minister Nawaz Sharif, 68, who is facing corruption charges in three cases.
Sharif's party (PML-N) had come second in the general election leading their party to denounce "the polls as rigged" and allege "the military and courts tipped the scale in favour of Khan's party".
Earlier, Shahbaz Sharif was taken to the Accountability Court in the strict security.
The former Punjab CM told the court that the case against him "was politically motivated". The PML-N has also chose to consult with other opposition parties on the contemporary issues. Mid-day accepts no responsibility or liability for its dependability, trustworthiness, reliability and data of the text.
"The government shouldn't put the burden of its incompetence on Shahbaz Sharif", the elder Sharif said.
Meanwhile, PML-N' s members of the National Assembly have submitted a letter to the NA speaker, requestioning a session of the lower house to discuss the opposition leader's arrest.
This Saaf Pani Company was established by Shahbaz's previous Punjab government to conceive, plan, design, execute and manage projects for the provision of safe drinking water in terms of both access and quality, to communities living in rural areas of the province.
Chaudhry said while the government was willing to assist NAB in administrative matters, the bureau was an independent institution which was not under the government.
Following an internal meeting among members of the Sharif family on Sunday, the top leadership of Pakistan Muslim League-N (PML-N) called an emergency Central Executive Committee (CEC) meeting tomorrow. Like other citizens, Shahbaz Sharif is also answerable to law.
Shehbaz was detained on Friday by the NAB in the Ashiana Housing scam.
"Shehbaz was summoned before the NAB in a different case and was arrested in another, such joke with the nation will not last long", he said.