Prime Minister Kevin Rudd is widely expected to use the Pacific Island Forum in Niue later this month to announce details of a trial plan to bring Pacific Islanders to Australia for seasonal work to plug labour shortages in rural areas.

The trial, to begin next year, would provide several thousand Pacific Islanders with special visas to work in rural areas facing severe labour shortages, including in Victoria and southern NSW.

Some unions have argued that the scheme will set a precedent for the use of cheaper foreign labour at the expense of Australian jobs.

Although the National Farmers' Federation strongly supports the scheme, the Construction Forestry Mining and Energy Union and others have warned it will lead to the "Mexicanisation" of the labour market, exploiting cheap labour while resulting in lower wages and worse conditions generally.

But it is believed the scheme, which will allow workers to visit for six to 12 months, will guarantee the same wages as those received by Australian workers to allay concerns it will undermine conditions and awards more generally. Accommodation, travel and housing will also be provided.

The Government is also worried the issue will become politically fraught amid claims the scheme will raise the risk of overstayers and the introduction of criminals or people with communicable diseases.

Overseas sources have warned that a large guest worker scheme could draw much-needed skilled workers from their own countries, limiting developmental opportunities.

Opposition foreign affairs spokesman Andrew Robb is claiming the Government is trying to "sneak" the scheme through without proper public consultation.

"There's been absolutely zero detail," he said last week.

"Does Australia want unskilled labour coming in from a number of Pacific islands given there are half-a-million unemployed people in our country already?"