Advocates are warning how important hearing testing is for children's development and relationship harmony as part of Hearing Awareness Week, from March 3 to 9.

Australians young and old are being urged to get their hearing tested during Hearing Awareness Week (March 3-9), with research showing how important it is for both children's development and relationship harmony.

Australian Hearing research found that 18 per cent of parents have never had their children's hearing tested, or are unsure if they have.

Principal audiologist Samathan Harkus said 75 per cent of parents haven't had their child's hearing checked before they started primary school, despite the majority recognising hearing loss can lead to learning difficulties and behavioural problems.

"We want our children to be using their energy to learn in class and be social in the playground, rather than focusing on trying to understand what they're hearing," she said.

Australian Hearing also commissioned research into "domestic deafness" - the idea that your partner is ignoring you.

Principal audiologist Emma Scanlan said many people joked about the concept of "selective hearing", but extrapolating from their survey of 1274 people, found it could be affecting 2.7 million Australians.

"What might be a surprise is that it could be as a result of undiagnosed hearing problems, and a simple hearing test can reveal that," she said.

Australian Hearing has encouraged people to take a free test at bigaussiehearingcheck.com, and help end the stigma of hearing loss.

The organisation has also received a $4 million grant from the federal Department of Health to rollout a free hearing test for children called Sound Scouts.

The app selivers a user-friendly hearing test and information on how children can be referred for further testing and appropriate support for hearing problems.