A local court issued arrest warrants of Makhdoom Shahabuddin and Ali Musa Gilani, the son of former Prime Minister Syed Yousuf Raza Gilani in ephedrine case.
Rawalpindi’s local Magistrate Shafqatullah issued the arrest warrant of Makhdoom Shahabuddin, tapped for the post of premiership.( just a day after he was nominated).
Makhdoom Shahabuddin's arrest warrant is linked to imports of an illegal drug while he was health minister.
Parliament is due to vote on a new PM on Friday to replace Yousuf Raza Gilani. The Supreme Court disqualified him because of a contempt conviction.
It is not clear if the warrant will derail Mr Shahabuddin's nomination.
Legal experts say that even if he is arrested, he could still be elected prime minister by parliament, the BBC's M Ilyas Khan in Islamabad reports.
Mr Shahabuddin is a senior figure in the ruling Pakistan People's Party who served in the cabinet of Benazir Bhutto and was most recently textiles minister in Mr Gilani's administration.
The order for his arrest was issued by an anti-narcotics court judge in the northern city of Rawalpindi.
It is linked to an anti-narcotics force case into the illegal importing of the drug ephedrine while he was health minister.
Mr Shahabuddin is accused of violating restrictions on the import of the drug in 2010. He denies the charge, and says he in fact ordered an inquiry into the affair.
State TV said that another minister, Raja Pervez Ashraf, would be offered as a "covering" candidate in case the textiles minister was rejected by MPs.
Feud with judiciary
The court's decision to disqualify Mr Gilani stunned Pakistan's government on Tuesday, two months after judges convicted the prime minister of contempt of court for failing to pursue corruption charges against the president.
In April, Mr Gilani was given a token sentence and avoided a jail term.
Even if Mr Shahabuddin does become prime minister, he is likely to face the same Supreme Court demand as Mr Gilani for the launch of a corruption inquiry into Mr Zardari.
The charges against President Zardari date back to the 1990s when his late wife Benazir Bhutto was prime minister. They were accused of using Swiss bank accounts to launder bribe money.
President Zardari has always insisted the charges against him are politically motivated.
Mr Gilani's removal as prime minister is being seen as part of a long-running and bitter feud between the government and judiciary.
Source: BBC & The Nation.pk