Mackenzie Miller weighed 670 grams when she was born at 23 weeks and five days in 2017.

Her parents Lauren and Richard Miller spent as much time as possible at the Royal Hobart Hospital cuddling their daughter.

Mackenzie Miller spent six months in hospital from the day she was born. ( Supplied: Lauren Miller )

"We knew that giving that positive touch … was incredibly important … to balance out the touches that weren't as lovely," Ms Miller said.

In the six months that Mackenzie spent in hospital, there was just one day the family couldn't be there, so Ms Miller decided to let a volunteer cuddle her baby.

"It meant so much to me that there was someone available to give her some love," she said.

The volunteer baby cuddling program at the RHH ensures premature babies can be held and cuddled even when their parents have to be away.

Waiting list for popular cuddling program

The program was started at the neonatal ward by retired nurse Judy Stove.

It's now so popular, there's a waiting list.

"I think it helps them grow because they're very calm and relaxed," Ms Stove said.

"There's nothing nicer than cuddling a baby really is there?"

Volunteer Judy Stove cuddles baby Declyn Triffitt as part of the program she helped set up. ( ABC News: Felicity Ogilvie )

Naomi Spotswood, a doctor in the neonatal intensive care unit, encourages parents to hug their babies as much as possible when it's safe for them to leave their cribs and to use volunteer cuddlers if needed.

"Medically, they're a little more stable," she said, adding their "social interaction … with the world" also benefitted.

"Just having that human connection [is really important], and some studies [show there are benefits for] growth from having human touch."

Nathalie Maitre, a neonatologist and director of the NICU follow-up program at Nationwide Children's Hospital in Ohio, studied the impact of painful medical procedures on babies' brains.

Dr Nathalie Maitre says gentle touching can help heal the pain of hospital procedures. ( Supplied: Dr Nathalie Maitre )

She said that when a baby was born premature, the brain was not developed enough to distinguish between painful touch and soft touch — cuddling teaches a baby to understand the difference.

"In these babies, even when they have lots and lots of painful procedures, if they also experience an abundance of gentle supportive touch it can help mitigate how that response to gentle touch was diminished by the painful procedures," she said.

Dr Maitre has first-hand experience of the importance of gentle touch, she regularly cuddled her own son in hospital when he was born premature 15 years ago.

She said the volunteers were doing a great job giving the babies and their parents the gift of human connection.

Back in Hobart, Ms Miller said her daughter still loved cuddles.

"She's very easy to soothe when she's upset we give her a cuddle and … it's what calms her every time," she said.