Pervez Elahi told Arab News, "I will be appointed the deputy prime minister through a constitutional amendment or an executive order."
Others from the PML (Q), who took oath as federal ministers were Wajhat Hussain, Amir Muqam, Ghaus Bux Mehr, Faisal Saleh Hayat and Riaz Pirzada.
Ministers of state and advisers include Waqas Akram, Rana Asif, Akram Masih, Raza Hiraj and Shahjehan Yousaf.
Some PPP leaders headed by Raza Rabbani opposed the deal.
"There is no room for a deputy prime minister within the framework of the constitution," leading lawyer Ahmad Raza Kasuri told the Arab News.
He said, this appointment will be challenged in the Supreme Court.
A PML (N) lawmaker, Syed Zafar Ali Shah said, "We will challenge the appointment of Pervez Elahi in the Parliament as well in the Supreme Court."
