The two major parliamentary parties have started their efforts to grab the top office of the upper house.
More than 130 candidates including those nominated by political parties and independent candidates were in the contest.
Polling was peaceful and no untoward incident was reported.
Winning control of the Senate could enable the PML-N to change the constitution to make party leader Sharif eligible to hold office again. Each senator serves a term of six years, barring resignation, disqualification, or other extraordinary circumstances.
Those candidates, who will be running as "independents", are expected to pledge their allegiance to PML-N if they are elected to the senate, PML-N party officials say.
In Punjab, the ruling party candidates shouted foul when Zubair Gul lost on a seat that was bagged by PTI candidate Chaudhry Mohammad Sarwar despite having poor representation of his party in the provincial assembly.
In case of non-compliance the controlling officer will cancel the ballot paper of such persons.
Italians vote in country's general elections
The anti-establishment Five Star party was founded in 2009 by comedian Beppe Grillo, who denounced cronyism in Italian politics. Sister Vincenza, voting at a polling station on Rome's Aventine hill, said the process was "all mixed up".
The opposition Pakistan Peoples Party (PPP) now controls the 104-seat senate but is expected to be replaced by the PML-N as the single biggest party.
The deposed prime minister also urged for accountability of those involved in horse trading and used money in the Senate elections. Those who won against the general seats include Sardar Shafiq Tareen and Abida Umar (PkMAP), Tahir Bijenjo and Akram Dashti (NP), Maulana Faiz Muhammad (JUI-F) and independent candidates including Anwarul Haq Kakar, Ahmad Khan, Kauda Babar, Sadiq Sanjrani, Naseeb Ullah Bazei and Sana Jamali. They can not use PML-N name and platform due to a recent Supreme Court verdict. Zubair Gul was president of the PML-N's United Kingdom chapter and had surrendered his United Kingdom nationality to contest the polls. 53 votes are needed for Chairman and Deputy Chairman.
But the trickiest situation is in Federally-Administered Tribal Areas (FATA) where 10 members of the National Assembly would elect four senators.
Policemen walk past in front of the parliament house in Islamabad.
"There is broad consensus that system of election for Senate is flawed and we need to improve it", Prime Minister Shahid Khaqan Abbasi had said ahead of polls.
Waheed Aalm said that time had come for every political party to do politics of elections.
This is unedited, unformatted feed from the Press Trust of India wire.