Nearly 2000 Australians have admitted voting more than once in the 2013 federal election, with one voter casting as many as 15 ballots.
Following the September poll, the Australian Electoral Commission investigated almost 19,000 instances of multiple voting.
Several thousand have been confirmed as being caused by clerical errors by electoral officials, the ABC reports.
However, Acting Electoral Commissioner Tom Rogers has told a Senate estimates hearing that his organisation is taking a closer look at nearly 2000 other cases.
Mr Rogers says the greater majority of those - more than 81 percent - were elderly, had poor literacy skills, or had a low comprehension of the electoral process.
