The decision of United Kingdom Unionist leader Bob McCartney, veteran victims campaigner Willie Frazer and Rainbow George to stand in several constituencies became an issue "surrounded by confusion," the Commission said.

Its report into the last Assembly election also said the traditional role of polling agents in Northern Ireland has been made "largely redundant" with the introduction of requirements for photographic ID at polling stations.

It warned that "the behaviour of a small minority of polling agents had an impact on the smooth running of the poll, leading, in some cases, to perceptions that polling agents undermined the electoral process."

And the report added that a balance had to be struck between the legitimate presence of political party representatives within the polling place, the right of voters to cast their ballot in secret and the requirement for polling staff to administer the elections "in an atmosphere free from intimidation."

It also revealed the Assembly elections which led to the return of devolution cost almost £4 for every person who voted - although the administration costs still came in on budget.

There was also a significant decrease in the number of spoilt votes - and 99% of voters experienced "no difficulties" with electoral identification on polling day.

And the Commission said while perceptions of electoral fraud persist among the public "the reality does not match up".

As the report was published, there had been no allegations about electoral fraud on polling day to the Commission or PSNI.

Electoral Commissioner Karamjit Singh said: "Elections in Northern Ireland have undergone considerable transformation in the last few years.

"Changes such as individual registration, and the requirement for photographic ID at polling stations, have paved the way for elections that are now largely free from allegations of electoral fraud.

"Our report also bears witness to increased levels of satisfaction with the voting experience - a solid foundation which will support our drive for increasingly high standards in the running of elections across the UK."