Pakistan's de facto interior minister Rehman Malik, a close aide to President Asif Ali Zardari, resigned from parliament on Tuesday amid a controversy about his dual nationality.
The Supreme Court suspended Malik's membership of the upper house of parliament, the senate, on June 4 for allegedly running for office while still holding British citizenship.
The court ruling disqualified Malik from his post as interior minister, but he stayed on as the prime minister's "advisor" on interior affairs.
"I have decided to resign from the Senate and have conveyed my decision to the party leadership. I am willing to fulfil any other responsibility which my party will assign me," he told reporters in Karachi.
Minutes before Malik's announcement, a bill was introduced in parliament to do away with the constitutional clause which bars MPs from acquiring foreign nationality.
"I decided to shun my membership because people are attaching the proposed amendment in the dual nationality law with me," Malik said.
"So I have given up my membership and will now openly campaign for this bill for the sake of 1.2 million fellow overseas Pakistanis."
Malik, elected to the Senate in 2009, had earlier told the Supreme Court he renounced his British citizenship and promised to submit documentary evidence in court.
But a certificate presented to a three-member bench headed by Chief Justice Iftikhar Muhammad Chaudhry failed to satisfy the judges.
Last month, the Supreme Court temporarily suspended MP Farahnaz Ispahani, the wife of Pakistan's sacked ambassador to Washington and an advisor to Zardari. She holds dual Pakistani-US nationality.