Even though the Constitution prohibits overseas Pakistanis and dual-nationality holders from voting, since 1993, there have been many attempts to make an amendment to grant rights for Pakistani living abroad to have rights to vote as there are around 8 million people living abroad, primarily in the Gulf states, United Kingdom, United States, and in Asia.
After several statements to the Court by the ECP and Caretaker Government reiterating their inability to institute the necessary arrangements, the Court accepted that overseas voting would be instituted for subsequent elections. On 9 May 2013, President Zardari signed the Election Laws (Amendment) Ordinance, providing for the right to vote for overseas Pakistanis.
The Election Commission of Pakistan has re-constituted the Special Committee on right of vote to overseas Pakistanis under the Chairmanship of Secretary, Election Commission of Pakistan including the representative from Prime Minister’s Secretariat, Ministry Overseas Pakistanis, Ministry of Foreign Affairs, Ministry of Law & Justice, Ministry of Parliamentary Affairs, Ministry of Finance, National Database &Registration Authority (NADRA), Overseas Pakistanis Foundation (OPF) and offices of Election Commission of Pakistan.
However, many Overseas Pakistanis, especially in the United States, are not allowed to keep their Pakistani citizenship if they become naturalized citizens there, in such a situation, they will not be able to vote for representation in Pakistani legislatives.
Representation of overseas Pakistanis in the National and Provincial Assemblies
Besides, Minister for Overseas Pakistanis has desired to make legislation for allocation of seats for overseas Pakistanis in National & Provincial Assemblies. Ministry of Parliamentary Affairs was requested to make legislation for allocation of seats for overseas Pakistanis in National and all Provincial Assemblies or alternatively advice this Ministry regarding further proceeding in the matter. Ministry of Parliamentary Affairs has forwarded the views of the Election Commission of Pakistan that Chief Election Commissioner has constituted a Special Committee on the right of vote to overseas Pakistanis. The Committee has been mandate to consider the issue including allocation of seats to the overseas Pakistanis in the National & Provincial Assemblies and explore some viable solution in 2009.
Representation in the National Assembly is allowed to the provinces on the proportional basis of their population. Allocation of one seat each to every province irrespective of its overseas population will negate the basis of representation in the National Assembly.
Source
http://www.ophrd.gov.pk/gop/index.php?q=aHR0cDovLzE5Mi4xNjguNzAuMTM2L21vb3BzbS9mcm1EZXRhaWxzLmFzcHg%2FaWQ9MjMmYW1wO29wdD1uZXdzZXZlbnRz
https://en.wikipedia.org/wiki/Overseas_Pakistani
http://thecommonwealth.org/sites/default/files/project/documents/Pakistan%20General%20Elections%202013%20Commonwealth%20Observer%20Mission%20Report.pdf