The Northern Ireland Office has pledged to help speed up the counting process for future elections.
Sinn Fein MLA Francie Molloy has made an official complaint to the Electoral Office over the slowness of the count in the Assembly poll.
It was 27 hours from the first to the final result in Mr Molloy's Mid-Ulster constituency. Minister Hugo Swire said he understood people's frustration at the delay.
"After any election, the Government reviews events and examines lessons to be learned with the chief electoral officer and the Electoral Commission," he said. "In light of the concerns expressed, I will ensure that work is taken forward to find ways to help speed up the counting process for future elections."
It took until Friday evening for the first results to be returned. Conor Murphy of Sinn Fein topped the poll in Newry and Armagh, followed by the UUP's Danny Kennedy and the SDLP's Dominic Bradley.
The Electoral Office said staff worked hard to process around two million ballot papers. They were also dealing with polls for local government and the AV referendum. Counting a Single Transferable Vote ballot, in the Assembly election, is a slow process, the electoral office said.
Mr Swire said: "Holding three polls at the same time was an unprecedented challenge for the Electoral Office and all those involved in the administration of the process. I am grateful to the chief electoral officer and all those who worked tirelessly in the run-up to, during and after these polls for their efforts."
He added that the chief electoral officer's main priority was getting it right and ensuring that all Assembly members and councillors were properly returned. Mr Swire said he had achieved this.
"However, I know that many people have expressed concern about the time taken for results to become known at the Assembly election count, which was caused mainly by the need to verify three sets of ballot papers on the day after the poll," he said.
"I understand their frustration and am grateful to elections staff for working particularly hard to ensure that the Assembly count was completed by the end of the second day of counting, as planned."