More election helpline staff due to 'unprecedented demand'
More staff have been assigned to the Electoral Office helpline due to the "unprecedented demand" of running two separate elections at the same time.
It has been reported that some voters have faced delays getting their postal or proxy ballot requests approved.
The office said it was aware some people were unhappy with waiting times on the helpline.
Local elections will be held on Thursday and European elections on 23 May.
Virginia McVea, chief executive of the Electoral Office of Northern Ireland, said people could email queries if they wanted, instead of phoning.
The Electoral Office has 8,500 staff working on the two elections.
What is a postal ballot?
Votes can apply for a postal vote if they want to vote by post. Voters must complete an application form specifying the reason why they cannot go in person to vote at their polling station.
What is voting by proxy?
Voting by proxy means getting someone to vote on your behalf. Voters must complete an application form specifying the reason why they cannot go in person to vote at their polling station.
The Electoral Office also said it was facing the challenge of doubling the use of polling stations so they can be used for the European elections as well as the local elections.
All council seats on all 11 councils in Northern Ireland will be up for election on Thursday.
The UK had not been expected to take part in European Parliamentary elections in 2019, but this changed after the Brexit date was delayed to October 31.
The European election still may not take place if a Brexit deal is agreed before polling opens.