A poll commissioned by the Elections Department (ELD) and done by the Government feedback unit Reach found that seven in 10 respondents were satisfied with their experience at polling stations.
The fact that the other three in 10 had a less than satisfactory voting experience is "not acceptable", the ELD said yesterday.
"We apologise for this, and thank voters for their patience," it added.
The poll also found that those who voted in schools and community clubs or centres, which typically house polling stations that serve larger numbers of voters, reported poorer voting experiences because of the length of time it took to vote.
The survey was carried out between July 23 and 30, and involved more than 1,000 Singaporeans above the age of 21. The results were weighted by gender, race and age to ensure they are demographically representative.
Around 78 per cent felt the polling process was well organised.
About 17 per cent were neutral and 4 per cent disagreed.
Asked if election officers were helpful to voters when carrying out their election duties, about 77 per cent agreed, while 20 per cent were neutral and 4 per cent disagreed.
About 80 per cent said they spent less than 30 minutes for voting. A further 9 per cent said they took 45 minutes or more to vote.
Voter satisfaction decreased significantly when voters had to wait longer to vote.
The ELD noted that a "cliff effect" was observed when the voting time reached 30 minutes.
While 84 per cent of voters who took less than 10 minutes agreed they were satisfied with their overall experience at the polling station, only 54 per cent of those who took between 30 and 44 minutes agreed.
Only one in 10 of those who took longer than an hour to vote said they were satisfied.
The ELD said yesterday that it will improve its systems and processes as it prepares for future elections.