Feuding couples can tell each other where to go but their counsellors won't be able to.
The federal government is offering $200 vouchers for couples to undergo relationship counselling.
From July, 100,000 couples will undergo a trial by registering online for the subsidy.
Senators at a committee hearing on Thursday expressed concern that same-sex couples could be shown the door by conservative-minded counsellors.
The Department of Social Services assured them that to get government funding, service providers have to demonstrate they are willing to work with a diverse range of couples with different backgrounds and beliefs.
"They can't tell them where to go," deputy secretary Barbara Bennett told the hearing.
"No, they might be telling each other that," Liberal senator Sue Boyce offered.
