Eight of the witnesses are from the FIA, who will record their statements against Asif Zardari and 30 other accused.
NAB (National Accountability Bureau is an autonomous and constitutionally established federal office primarily responsible for efforts against corruption.
NAB officials claimed that delaying tactics were being employed by the alleged to drag the case.
'NAB chairman wants to make politicians controversial'
The hearing was adjourned till May 30
NAB has summoned record of the procurement of motorcycles for the Dolphin Force
Wattoo served as federal minister of industries and production in year 2008.
NAB has decided to file a supplementary reference in the Harish and Company case
"This is the last time I am appearing before NAB, after this NAB will cease to exist," said Zardari.
Mr Afzal has been asked by the anti-graft watchdog body’s Lahore chapter to appear before it today at 3pm.
The latest summon was issued for May 16 again as Zardari had excused to appear before NAB on May 9.