Around 50,000 people were visiting the website per minute which slowed it down, Geo News reported.
The Pakistan Telecommunication Company Limited (PTCL) decided to shut down the website to avoid any loss.
A senior technical official from the ECP said measures were being taken to restore the website.
The report said the closure of the website indicates as to what extent people were interested in the claims made by the candidates in the nomination papers.
Polling for the 342-member National Assembly or lower house of parliament and four provincial assemblies will be held on the same day May 11.
Candidates can withdraw papers by April 17 and the final list of candidates will be issued April 18.
The total number of registered voters in the country until March 20 was 86,132,751 voters, including 48,572,097 females, the Election Commission said.
--IANS (Posted on 01-04-2013)