The industrial inspectorate has confirmed it is investigating the employment practices of the Church of Scientology.
Fair Work Ombudsman Nicholas Wilson told a Senate estimates hearing it had looked into the controversial religious group but declined to give details.
It is understood opposition frontbencher Eric Abetz wrote to the ombudsman in March with the idea of an inquiry.
The inspectorate has subsequently interviewed Scientology members along the east coast of Australia to establish whether they are being properly remunerated for their church work.
Asked by independent Senator Nick Xenophon if children were working within the organisation, the Fair Work Ombudsman was coy.
"We don't confirm or deny whether that is likely what they're doing," Mr Wilson told the Senate hearing.
"As a matter of policy, the assertion that ... children are underpaid in and of itself means nothing to the investigation.
"What that means in this particular investigation I don't want to say."
The Senate economics committee is expected to hear evidence from former Scientology members in late June.
It is receiving submissions into a possible public benefits test for charitable and religious groups after Senator Xenophon moved a private senator's bill in May.
He had tried unsuccessfully in March to have a Senate inquiry examine the tax-free status of religious groups, including Scientology.
The government and the opposition also used their numbers in the upper house to defeat his call for an inquiry to look at specific allegations against the church made by former Scientologists.
