Nawaz was speaking to the media in London after a meeting of PML-N bigwigs, who reportedly chose to remove Finance Minister Ishaq Dar in the wake of NAB probe against him.
Answering a question about election campaign of two candidates - including one linked to banned Lashkar-e-Taiba chief Hafiz Saeed's group and the other from the Labaik group - Nawaz said such precedents were risky for Pakistan and the democratic forces.
The much-awaited verdict in what came to be known as the Panama Papers case stunned the ruling Pakistan Muslim League-Nawaz, which put up a fearless front saying all was not over for Sharif and he would remain its leader.
So far, the NAB has filed three corruption and money laundering cases against Sharif, his family and Safdar, while it has also filed one case against Dar in the Islamabad Accountability Court.
The court will most likely issue bailable or non-bailable arrest warrants for the former prime minister, Nawaz Sharif, and his family members if they do not turn up in court after receiving the summons. Nawaz said he had requested Khaqan Abbasi to "personally investigate as to why they were kidnapped and who was responsible for it".
The meeting will review the Electoral Reforms Bill, 2017 that was passed by the Senate on Friday without amendment in Section 203.
According to a private TV channel, the Saturday's meeting chaired by Nawaz made a decision to take resignation from Ishaq Dar after detailed discussions on the issue.
The National Accountability Bureau (NAB) pasted two notices on the main gate of former prime minister Nawaz Sharif's Jati Umra residence on Friday, restraining him from selling the residential property and summoning him to appear before Islamabad's accountability court on Sept 26.
A five-judge bench of the Supreme Court on July 28 had directed NAB to file references against Mr Sharif and his children within six weeks in the accountability court, which was asked to decide the references in six months.
He said consultations among party leadership was a routine matter and it would continue. "Pakistan cannot afford such things, as the situation can take a unusual and unexpected turn", he said.
Earlier, after his meeting with Nawaz, Prime Minister Shahid Khaqan Abbasi said that democracy won in the NA-120 by-polls.
He branded that democratic forces like PML-N are to suffer if reports of "religious parties being funded" true.