The Australian Electoral Commission says data from the last federal election in 2010 revealed that electorates with the largest number of informal votes cast were also the electorates with large numbers of voters whose first language is not English.
The AEC is distributing voting information in 27 languages through its website and community newspapers in a bid to reduce the informal vote in the election on September 7.
Michael Kenny reports.
Data from the previous election shows the level of informal or invalid votes was over ten per cent in six Labor held seats in western Sydney, all with large numbers of voters from a non-English speaking background.
In the seat of Blaxland, held by Home Affairs Minister Jason Clare, the informal vote was 14 per cent.
Bureau of Statistics figures from the 2011 Census show that two or more languages were spoken in two thirds of households in the Blaxland electorate.
The other western Sydney seats - Fowler, Watson, Chifley, McMahon and Greenway - all had informal votes of over ten per cent at the 2010 election.
A spokesman for the Electoral Commission, Phil Diak, believes many voters from a non English speaking background may be struggling to understand the complex voting system for the House of Representatives.
"The Australian full preferential system for federal elections- it's not a common one. It does exist in the world, but it's very likely that new Australian citizens haven't experienced it overseas and perhaps compounding that there is a difference, for example in NSW between voting in state elections for the lower house and voting in federal elections for the equivalent House of Representatives."
In New South Wales state elections, voters casting ballots for lower house seats only have to number one box with their first preference in order to cast a formal vote.
But for federal elections across Australia, voters need to number every box on the House of Representatives ballot paper in order for their vote to be counted.
Similar differences between state and federal voting don't occur in other states.
Associate Professor Sally Young from the University of Melbourne has conducted extensive research on informal voting in Australia.
She believes language barriers are one of the main factors behind the problem.
"It's a problem with areas with high concentrations of people from non English speaking backgrounds. But New South Wales is one of the areas where we see a particularly high proportion of informal votes. That's definitely an issue for New South Wales and one I know the Australian Electoral Commission tries to address in a number of ways including putting pamphlets in peoples' own languages and trying to do education programs to inform people about correct voting methods."
Dr Young says there is less informal voting in other parts of Australia, including in seats with large migrant populations.
In the north-western Melbourne electorate of Calwell, for example, there was an informal vote of 6.5 per cent at the last federal election.
Figures from the 2011 Census show that two or more languages were spoken in over 40 per cent of households in that electorate.
Dr Young says while some voters in every electorate may be deliberately casting informal votes, she believes the current voting system could be confusing many Australians, particularly in New South Wales.
"There's quite a high standard for voting in Australian elections. There aren't many places in the world where you have to number every box on a ballot paper and those ballot papers are getting longer and longer. So it is an ask of citizens to do that and we need to make every effort to facilitate them to be able to do so."
Dr Young says data from the Electoral Commission shows the level of informal voting is much lower for the Senate than for the House of Representatives.
She says this is true for all electorates.
For example, the western Sydney seat of Blaxland had an informal vote of 14 per cent for the House of Representatives, compared with eight per cent in the same electorate for the Senate.
Dr Young says informal voting is high in some marginal seats too, including the most marginal seat in New South Wales - Greenway in Sydney's north-west.
Greenway is held by Labor's Michelle Rowland by a margin of 0.88 per cent.
If the 9,000 voters, or ten per cent of the total, who cast an informal vote at the last election in Greenway had cast a valid vote, that could have changed the result in such a close seat.
The Electoral Commission says it's trying to reduce the number of informal votes by recruiting more bilingual staff and volunteers at polling booths who can explain the voting process.
It says it has recruited 80 bilingual volunteers to work at western Sydney polling booths alone on the day of the election.
Pino Migliorino, from the Federation of Ethnic Communities Councils of Australia, says it's critical for the country's democratic system to ensure all Australians are fully aware of how to cast a valid vote.
"It is a democratic process and what we need to do is limit the impact and I am using this word in a very specific way- the 'ignorance' of the electoral process and electoral literacy, if you like, and I think that's absolutely essential. We should not have elections or results of elections based on people's lack of understanding of the system. It should be them casting a vote for what policies and programs they believe in."
Data from the Electoral Commission also suggests that language barriers could be linked to higher levels of informal voting in seats with larger numbers of Indigenous voters.
Over 40 per cent of voters in the Labor held seat of Lingiari in the Northern Territory are Indigenous Australians.
Over 25 per cent of the electorate come from households where two or more languages are spoken, including at least five Indigenous languages.
At the 2010 federal election, the number of informal votes cast in Lingiari was 7.5 per cent.
Phil Diak from the Electoral Commission says polling officers from an Indigenous background are working in seats like Lingiari to try and get the message across about how to vote in Indigenous languages.
"Especially in the Northern Territory, although not exclusively- it also happens in Western Australia, South Australia and parts of New South Wales and Queensland as well- We've also been taking a longer run initiative with the Indigenous Electoral Participation Program which was established in 2010. There have been 20 outreach officers there of Indigenous heritage who have been working extensively with communities."
The 27 languages with information on the Australian Electoral Commission website are Arabic, Assyrian, Bosnian, Burmese, Cantonese, Mandarin, Croatian, Dari, Dinka, Farsi, Greek, Hindi, Italian, Khmer, Korean, Lao, Macedonian, Polish, Portuguese, Russian, Serbian, Spanish, Tagalog, Tamil, Thai, Turkish and Vietnamese.
