The Australian government is spending an extra $20 million on childhood heart disease and $6 million on a national action plan to address the condition.

Kate and Alan Mainwaring didn't even know children could have heart issues until their own son Charlie was admitted to hospital at just three-and-a-half months old.

The Canberra boy was initially undergoing treatment for being underweight and things were looking good as he began to gain weight.

But a week later his heart failed.

It was discovered Charlie's heart was four times the normal size and had a range of other defects.

"I think most people know (about heart issues) when their child's born - we didn't know," Ms Mainwaring told AAP.

"The first time we were going in blind. We had no idea that kids have heart problems."

Charlie soon underwent open heart surgery in Sydney, leading to a series of health incidents including a heart attack and a stroke.

Kate, Alan and Charlie were in Sydney for more than a month dealing with Charlie's heart issues, leaving their two other children at home, until they were given the green light to head home.

The parents wish they had known what they learnt from organisation HeartKids when Charlie required further open heart surgery at 18 months - that they could have brought their other two children with them, staying at Sydney's Ronald McDonald house.

"The second time after we kind of knew the ropes we heard about HeartKids and they were kind of providing advice for us," Ms Mainwaring.

The federal government is hoping to improve care for thousands of Australians like Charlie by spending $20 million on research focused on congenital heart disease - the kind people are born with.

The funding, allocated from the Medical Research Future Fund, will be provided through grants.

The government is also giving $150,000 to HeartKids to develop a national strategic plan for the condition and $6 million to implement it over six years.

Health Minister Greg Hunt says the plan will help co-ordinate policy changes to tackle the disease, improve care and support for those with it and raise community awareness.

"We are committed to doing more to support people battling this dreadful disease," he said.

Ms Mainwaring believes more research will make a difference to families like hers.

"It can help Charlie when he does need his valves replaced," she said.

There is currently no cure for congenital heart disease, which affects more than 65,000 Australians.

Eight babies are born with the condition every day, with four dying each week.