It's the third time in four years Birdsnest has won the award.

Birdsnest founder Jane Cay said customer service was critical.

"If we can make every customer experience a good one, girls have a network and they are going to tell their friends and that's how we've got along through word of mouth," she said.

"But I truly, really believe you don't have happy customers unless you have a happy team. I see my core responsibility as being to make sure everyone is happy and enjoying their roles and has an environment in which they can thrive."

Birdsnest has 129 employees, many of them mothers who enjoy flexible work arrangements. Ms Cay said the business also had a mindfulness program.

"We have a meditation at least once a day," she said. "It's all voluntary but I think the trickle-down effect of that is understanding stress and how good it is to nurture yourself."