The party of ex-Pakistan Prime Minister Nawaz Sharif says it will not boycott the country's new parliament despite reservations over the election results.
Former cricketer Imran Khan, whose PTI party has a clear lead in results reported so far, has claimed victory.
On Friday, a senior leader of Mr Sharif's PML-N party said the outcome of the parliamentary vote would be accepted for the sake of democracy.
The party alleged vote rigging had taken place during Wednesday's poll.
On Friday, a European Union monitoring team said the election campaign featured a "lack of equality".
"Although there were several legal provisions aimed at ensuring a level playing field, we have concluded that there was a lack of equality and opportunity," chief observer Michael Gahler told reporters.
"Candidates with large political appeal and financial means - the so-called 'electables' - often dominated the campaign."
Mr Khan, 65, has faced accusations that his election challenge benefited from military interference, a claim both he and the army deny.
On Thursday the charismatic leader - who captained Pakistan to a World Cup victory in 1992 but has long since shed his celebrity playboy image - said the vote had been the "clearest, fairest election Pakistan has ever had".
Can Imran Khan change Pakistan?
Why Pakistan's election matters
The election was seen as a contest between Mr Khan's Pakistan Tehreek-i-Insaf (PTI) party and Mr Sharif's Pakistan Muslim League-Nawaz (PML-N).
An official confirmation of the vote is still to come.
What has Sharif's party said?
A senior leader of the PML-N, Hamza Shahbaz Sharif, said the party had "reservations" over the way the election was held, but said it would concede victory in order to "strengthen democracy in the country".
"We are going to sit on opposition benches, despite all the reservations," the former prime minister's nephew said.
"Even if democracy is flawed, its solution is more democracy, and then more democracy."