"Honourable speaker, as for resignations, I resign from my seat...I am going back to the people of Pakistan," Dawn online quoted him as saying during a joint session of parliament.
He said that no PTI member resigned willingly. "People did not resign of their own will but I am resigning now," he said.
Earlier, PTI had submitted resignations of 34 lawmakers in parliament in protest against the government. However, Speaker Ayaz Sadiq did not accept their resignations saying he had not been present when they were submitted.
Hitting out at Prime Minister Nawaz Sharif Hashmi said, "Why didn't the PM go to the Senate for 14 months?
"Nawaz has been given chances many times...but Pakistan is not in a prosperous state," Hashmi said.
"People wanted to exclude Mujibur Rehman...said they wanted to be rid of Bengalis - how are we better off? Bangladesh is far more prosperous than Pakistan now?"
He also criticised PTI chairman Imran Khan for going back on his promises. "People say why I didn't come out with the truth before but I was trying to convince PTI members. Imran promised me he won't go against the constitution."
Despite his rift with the party, Hashmi said he was still the elected party president. "I thank people of Multan, Lahore, Pindi, Islamabad for all the times they've elected me as representative. I am still the elected president of PTI."
Hashmi claimed Monday that the ongoing political crisis in the country was following a script dictated by the military.
The anti-government protests led by PTI chairman Imran Khan and Pakistan Awami Tehreek (PAT) chief Tahir-ul Qadri began Aug 15 in an attempt to topple Sharif, who is accused of rigging the 2013 general elections.
The protests turned violent late Saturday and Sunday and as a result, at least three people were killed with over 450 protesters injured.