The FIR includes Sections 34 (acts done by several persons in furtherance of a common intention), 506 (punishment for criminal intimidation), 420 (cheating and dishonestly inducing delivery of property), 471 (using as genuine a forged document) and 468 (forgery for purpose of cheating) of the Pakistan Penal Code.
A tweet posted on the party's official account showed a man, believed to be Zaidi, being escorted to a white vehicle by men in civvies, with uniformed police personnel surrounding the scene.
In another footage, officials are seen dragging and pushing the former minister at the party secretariat. According to PTI spokesperson Farrukh Habib, the arrest was carried out by Sindh police.
The party claims that Zaidi was taken into custody without a warrant and moved to an undisclosed location.
Meanwhile, Imran Khan said on Twitter, "Strongly condemn arrest of another of our senior leaders, Ali Zaidi from Karachi. All part of the London Plan where Nawaz given assurances PTI would be crushed."
He added, "Over 3000 PTI workers arrested, abducted, terrorised. Ali Amin & now Ali Zaidi abducted. A new plan underway for more."
Predicting that more action is to come in Zaman Park after 27 Ramazan or over Eid, he said. "They think this will weaken us in case elections are held. Let me state categorically this will not work."
Imran said that people's anger is only increasing. "They will see the blowback of this nefarious London Plan in elections."
The party's chief and other leaders are facing cases on various counts following the Zaman Park standoff with police last month.
PTI workers had put up a strong resistance against the police's attempts to arrest Imran, and fired petrol bombs at them.
The former premier is of the stance that the government is resorting to such measures to avoid the polls, scheduled to take place in Punjab on May 14.