New South Wales’ online voting system was suspended for six hours because of an error on the Upper House ballot paper for the state election.

The NSW Electoral Commission (NSWEC) “paused” the iVote system after two parties were omitted from a section of the paper.

The iVote system is available to voters who are vision-impaired, have reading difficulties, live more than 20km from their nearest polling station or will be interstate or overseas on election day.

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The Animal Justice Party and the Outdoor Recreation Party were left off the “above the line” section of the paper, the ABC reports.

By 5pm Tuesday the iVote website was back up and running.

“Voting has restarted on the iVote(R) system. The iVote Legislative Council ballot paper now correctly shows group voting squares for Groups B and C. We apologise for any inconvenience,” a statement on the website said.

About 19,000 voters had used the system to cast their votes using the phone or internet since it opened Monday.

Electoral Commission spokesman Richard Carroll said earlier on Tuesday anyone concerned about how they had voted would be able to re-vote once the system was restored.

“The issue was the way the Legislative Council, or Upper House, ballot paper was being displayed when people went to vote using the system,” he said.

“The group voting squares for groups B and C were not there, so if people wished to vote for those candidates they simply needed to number the candidates from that group below the line.

“As soon as we noticed there was an issue, we suspended voting at about 11am (Tuesday). We expect the system to be back online by about 5pm.”

The news about some of the problems with ivote -&especially the invitation to de-register !!!-is very troubling. Suffrage for pwd? #nswpol

— Jess Cadwallader (@JessPWDA) March 17, 2015

Wow the NSW Electoral Commission has suspended iVote due to an error on the Upper House ballot paper… geez.

— Osman Faruqi (@oz_f) March 17, 2015

@TonyHWindsor #nswPol #nswVotes #IVote system is suspended. The I-Vote ballot paper has been produced wrong. Massive drama for NSW Elections

— Andrew Thaler (@andrew_thaler) March 17, 2015