Federal ministers Amanda Vanstone and Kevin Andrews are at odds over plans by American Express to have Japanese workers take jobs at a Sydney call centre.

The federal government is considering a proposal by credit card giant Amex to bring in 160 Japanese workers under the 457 visa scheme, which allows companies to sponsor foreign workers to fill skills shortages.

Senator Vanstone, the immigration minister, said under Amex's plan, the Japanese workers could be employed at below the award wage.

But Mr Andrews, the workplace relations minister, warned companies they cannot bring foreign workers to Australia on the visas and pay them less than the government-imposed minimum of $41,850.

In a letter to NSW Premier Morris Iemma last month, Ms Vanstone said they would be paid $6,000 less than the minimum.

Senator Vanstone said it was a choice between allowing the Japanese to work at the call centre which serves customers in Japan, or losing about 70 Australian jobs.

The salary on offer is lower than we would now allow for a metropolitan area, but I'm told it's commensurate with what other Australians are being paid in the centre, Senator Vanstone told reporters in Adelaide on Friday.

However, Mr Andrews warned against paying less than the award.

Let me make this absolutely clear to Amex and to any other company in Australia - don't bother coming to the government with proposals like this because they will be rejected, Mr Andrews told reporters.

The Finance Sector Union (FSU) said Senator Vanstone was bowing to Amex's threats to move the call centre to China if the Japanese weren't allowed in.

The government shouldn't be party to these threats, said FSU national secretary Paul Schroeder.

The increasing threat of taking jobs offshore is putting downward pressure on wages and the government should step up to stop that.

The federal opposition and NSW Labor government also slammed the Amex proposal, saying it was a result of the federal government's Work Choices scheme cutting Australian jobs and wages.

What we're seeing now is the routine rorting of the 457 visa, said federal Opposition Leader Kim Beazley.

It's been turned from an instrument ... encouraging the ability of work to be done in Australia into an instrument to be joined with the industrial relations changes to undermine Australian wages and conditions.

But Amex is adamant the Japanese will not be paid less than their Australian colleagues.

These people are being paid exactly the same as the Australian employee sitting right next to them, said Amex head of public affairs Luisa Megale.

Amex said it simply cannot find enough Australians with the advanced Japanese business language skills required for its Japanese Platinum Card Service Centre.

More than 250 Australians work at the call centre and Amex claims it has completely tapped the local bilingual market.

While unions claim the plan would cost Australian jobs, the positions were taken from Japanese workers in the first place when Amex moved the centre from Tokyo to Sydney in 2002.

By seeking to employ native speakers from Japan, Senator Vanstone said Amex was trying to avoid the similar frustrations many Australians encounter with offshore call centres.

Every Australian understands how annoying it is to ring a call number and get someone on the other end who doesn't clearly understand your cultural situation, she said.

That is what Amex is trying to fix.