DFAT introduced a working group on protections for domestic workers working for diplomats or consular officials in 2014, but the measures, and the time it has taken to introduce them, aren't enough, according to an advocate.

It was revealed this week that more than 20 domestic workers in diplomatic residences had sought help from the Salvation Army, with many cases coming from Canberra. Three workers told their stories of being underpaid and exploited to ABC's Four Corners program.

In a submission to a government inquiry on introducing legislation to combat modern slavery, the department said it provides information to the diplomatic corps "on expectations and obligations for fair treatment of private domestic workers" as well as issuing identity cards to domestic workers and requiring them to undertake annual interviews with DFAT officials.

However, these measures are easy to circumvent, according to Heather Moore, national policy coordinator at the Salvation Army's Freedom Partnership.

"There remain some pretty critical gaps in these reforms, and this is a global issue where the diplomats circumvent the process by bringing workers in on diplomatic visas," she said.

According to Moore, the annual interviews with domestic workers only began recently, and can take place by phone, meaning a worker may not be truly independent of their employer at the time.

Information sheets provided by DFAT to domestic workers about their rights, and giving contact information for fair work and non government organisations are only available in English and Indonesian.

"The problem with the fact sheet is we have had people who are not only illiterate in English but illiterate in their own languages as well," Ms Moore said.

She said while the department has introduced English language requirements for domestic workers, she is concerned that this is also being avoided by employers in diplomatic residences.

"These are loopholes that are being exploited and we know they are being exploited," she said.

"During any face to face or telephone interaction with domestic workers, we offer the domestic worker phone translation in the language of their choice," DFAT told Fairfax Media.

"It's not that they're doing nothing, these things are falling a little short of what is really going to make a difference," Ms Moore said.

"We appreciate that the government is engaging and exploring ways to improve protection," Ms Moore said, but the pace at which the reforms have come lets down workers in vulnerable positions.

In a statement to Fairfax Media, a DFAT spokesperson said the department had already played a role in helping workers, but did not comment on individual cases.

"DFAT has played a mediation role in cases where the domestic worker has sought our assistance and provided their permission to raise their concerns with their employer. Where appropriate, DFAT has also put the domestic worker in contact with relevant Australian authorities such as AFP and the Fair Work Ombudsmen."

"'DFAT has had a long standing interest in ensuring the rights and obligations of domestic workers and their employees are clearly understood and applied. DFAT has worked closely with other government agencies to provide support to domestic workers including prior to a formal working group being established in 2014," the spokesperson said.