A worker's union says it is fighting to "win back" more than $150,000 total in unpaid wages for up to 46 workers at the new Perth Airport international terminal.

The Construction, Forestry, Mining and Energy Union (CFMEU) said one worker was owed up to $15,000 in unpaid wages with other workers owed as much as $10,000.

Several Chinese workers had also allegedly not been paid since they started work six weeks ago and were owed about $68,000 in total, the union said.  Some workers had also missed out on superannuation and long service leave, the union said.

A spokeswoman for project developer, Broad Construction Services, said the company had fulfilled its obligations.

“Broad has paid all monies due to the relevant subcontractor in accordance with contractual terms and conditions, and met its obligations for safeguarding payments and conditions for subcontractor employees,” she said.

But CFMEU state secretary Mick Buchan claims Broad Construction Services, a subsidiary of Leighton Holdings, has “turned a blind eye” to the situation.

Workers stood outside the gate of the project on Tuesday morning, refusing to work until the situation was resolved.  Mr Buchan met with Perth Airport representatives and said they had guaranteed payment of all outstanding money.

In the meantime, workers would receive $1000 while wage claims were being settled, he said.

Perth Airport chief executive Brad Geatches confirmed the airport had given an undertaking to ensure all sub-contractor employees were paid.