Wheatstone construction workers are to be on a four-week on, one-week off arrangement, which is a pretty standard roster for resources project construction.

Australian Manufacturing Workers Union Western Australian secretary Steve McCartney claimed the four-week on one-week off roster offered is aimed at shoring up any push by project proponent Chevron to get Enterprise Migration Agreements.

He argues the four-and-one arrangement is family unfriendly, and therefore, a disincentive for people going to work on the project. This would then help Chevron make its case for an EMA to bring in foreign workers.

Say it quickly enough and it almost makes sense.

It leaves out the extra costs of bringing foreign workers in. As a rule of thumb it can cost about $40,000 on average to bring a foreign worker into Australia by the time visa costs, overseas recruitment costs, and the cost of landing them here and acclimatising them was taken into account.

It also leaves out the high wages such workers would earn.

Further muddying the waters around this issue is what appears to be a bit of a demarcation dispute brewing.

The Australian Workers Union has struck a deal with major Wheatstone construction contract John Holland enshrining the four and one roster.

Energy News Bulletin understands there was petition going around Karratha at the weekend decrying the AWU deal, saying it did not speak for other unions, such as the AMWU, the Construction Forestry Mining and Energy Union and the Electrical Trades Union.

A Chevron spokesman said the company had no comment at this time.

McCartney is sticking to his EMA claim.

"It has been reported that Wheatstone is one of the projects with EMAs currently before the federal government," McCartney said.

"If Wheatstone is working towards an EMA, they should be doing everything within their power to both train and attract local workers, including putting in family-friendly rosters."

McCartney also pointed to an agreement Bechtel had struck on a Gladstone LNG project bringing in a three-on, one-off roster.

"The last thing we want to be doing as a country is putting pressure on the family," he said.

"Bechtel in Queensland understands that."