Sharif's ruling Pakistan Muslim League-Nawaz (PML-N) has fielded his wife from the constituency he vacated after the Supreme Court disqualified him from continuing in his office in July.
Pakistan Tehreek-i-Insaf of Khan, who has led a campaign and petitioned the Supreme Court seeking Sharif's ouster over the Panama Papers scandal, challenged the acceptance of Kulsoom's nomination papers on Thursday from Lahore's NA-120 constituency.
Petitioner Andaleeb Abbasi, a leader of the PTI, said Kulsoom's nomination papers contained contradictions.
"Kulsoom Nawaz holds a work permit of UAE, like that of her husband on which he was disqualified," Abbasi claimed.
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She also said that the nomination papers were accepted by the election commission despite her not appearing in person.
Rival Pakistan People's Party (PPP) candidate Faisal Mir has also opposed her nomination on the grounds that being the wife of a deposed premier she was not eligible to contest the election.
Several PML-N leaders believe that Kulsoom will replace current Prime Minister Shahid Khaqan Abbasi after winning the September 17 election. And Sharif will return to the Prime Minister's House as 'First Gentleman'.
Kulsoom had successfully led the party's movement for the release of Sharif, then incarcerated, after a military coup by former president Parvez Musharraf in 1999.