"Are you really taking the 'homo ballot'?", the official asked an old lady who asked for a voting slip for Åpen folkekirke (Open people's church), at a polling station in Oslo.
Several other voters witnessed the incident, and began to complain but the man was allowed to stay in position until an hour before polls closed.
"This isn't tenable and it's totally unacceptable," Eivind Eide, one of the voters told Norway's state boradcaster NRK. "This official obviously tried to influence the election. How can such a person be responsible for the election?".
Vilde Vevatne, an election official working at the same polling station, said the man had behaved strangely from the moment the ballot opened.
"He was making all these generalising comments, and almost whenever a vote came in he would say, 'this one's in favour of gay marriage', or 'this one's more conservative'. He also used the expression 'are you really taking that homo-ballot'. That's not the job of an election official."
The official, who NRK did not name, said he had not to his knowledge done anything wrong.
"I acted by the book and tried my best to inform people. I did the best I could for the community and didn't say anything that could offend anyone," he said.