The study followed up 225 babies at six years of age who had been involved in an earlier behavioural sleep study as infants.
Parents who reported problems with their babies falling asleep at seven months of age were offered interventions including controlled comforting or camping out, while a control group did not receive extra help.
Controlled comforting involves parents leaving their baby for short intervals before returning to comfort them if they are crying. Common periods are two, four, six, eight and 10 minutes, or five, 10 then 15 minutes.
Camping out is a more gradual method where parents sit next to their infant and slowly edge their chair out of the room.
The study found no evidence that these techniques were harmful to children's mental and behavioural health, nor did it have an impact on their sleep quality or stress levels at the age of six.
Dr Anna Price of Murdoch Childrens Research Institute in Melbourne said when the babies were followed up at the ages of one and two their sleep quality had improved.
Meanwhile, their mother's sleep patterns and mental health had also improved.
At the six-year-old follow-up, families were asked about their child's emotional and behavioural wellbeing and quality of life, and a saliva sample was taken to test for the stress hormone cortisol.
Mothers were also asked about their mental health.
Dr Price said it was important to emphasise that controlled comforting and camping out were different from "crying it out" (leaving a baby to cry for the entire night).
However, she said techniques such as those used in the study were only appropriate to use after six months of age, when children learn that when something moves out of sight, it still exists.
"For parents who are looking for help, techniques like controlled comforting and camping out work and are safe to use, so families and health professionals can really feel comfortable using them," Dr Price said.
The study, published online in the journal Pediatrics, said infant sleep problems were reported by up to 45 per cent of mothers in the second six months of life and doubled the risk of maternal depression.
But uptake of the interventions had been limited by unproven concerns about the long-term impacts, the study said.