Concerns are growing that Irish emigrants will remain in Australia after their visas expire as the economy continues to dip Down Under, the Sunday Independent has learned.

Migration experts anticipate a surge in "undocumented Irish," a crackdown on permanent visas being awarded and a swell in "anti-immigrant" sentiment in some Australian cities.

Conversely, an Irish support group in Perth says families are "fearful" of the slow down in the mining industry and are booking flights home

They say a wave of "quick car sale" adverts are appearing on a support group's website placed by Irish who want to get home as soon as possible.

Dr Mary Gilmartin, who specialises in migration research at Maynooth University, predicts problems with illegal Irish in Australia that could mirror the historic situation in the United States.

"The possibility of people translating temporary status into permanent status is becoming more difficult so I think there may be an increase in the number of Irish who are undocumented in Australia," said Dr Gilmartin.

"The Government have quite a tough entrance regime so they take checking visas quite seriously but I'm getting some sense that there are people staying on past the expiry date of their visa," said the author of new book Ireland and Migration in the 21st Century.

She said an "anti-immigrant sentiment" is also creeping in throughout the country.

Although the attitude appears to be mostly directed at refugees and asylum-seekers, some Irish emigrants are feeling the change in atmosphere, particularly since Tony Abbott became Prime Minister.

Dr Gilmartin forecasts "a slight increase" in Irish people returning from Australia.

"It will take a bit of time for the contraction of the Australian economy but because it's resource dependent I imagine it will happen over the next few years," she said.

However, a non-profit organisation representing over 9,000 Irish emigrants in Perth, have already noticed a sharp increase in return migration.

Eimear Beattie, president of Irish Families in Perth, said: "A lot of families who came out when the recession hit had a five-year plan in place that they would make hay while the sun was shining and return home when the green shoots start showing in Ireland".

However, they are also leaving because of the slowing of the mining industry in Western Australia and worries of facing another crippling recession.

"Western Australia is not what it used to be in terms of making money. The boom is over, house prices are going down so the Irish have the fear in them," said Ms Beattie, a native of Glenfin, Co Donegal.

"Adverts for quick car sales on the site were the warning bells," she said, adding that it's mostly families with young children and people who worked in the mining industry that are leaving.

Meanwhile, young Irish singles have migrated within Australia towards Sydney where there appears to be more job opportunities.

"Sydney still seems to be the boom place. House prices are still increasing and there are Irish entrepreneurs in Sydney advertising on our website - that has never happened before.

"Young people are leaving Perth and moving there instead," said Ms Beattie, a teacher who emigrated to Australia four years ago with her husband, from Tipperary, and their three children.

Despite the emerging downturn, the Beattie family are not homeward bound.

"We're very settled. My children are still learning Irish out here and playing GAA so we have everything that we had in Ireland, only here we can have a swimming pool at our house. Our lifestyle is fantastic," she said.

Sunday Independent