Keepers at Melbourne Zoo are "99 per cent sure" a baby western lowland gorilla born over the weekend is a girl as they prepare for the newborn's first public outing.

The tiny gorilla, born to 10-year-old Kimya on Saturday evening, has been so lost in her mother's thick fur that keepers had been puzzled over the baby's sex until now.

"It's been quite hard notice if it's a boy or a girl over the last few days, but we're 99 per cent sure that it's a girl," primate manager Harna Burton said.

She said newborn gorillas rely on their mother's body heat to keep warm.

"Kimya's been an amazing mum, from the moment it was born she hasn't put it down," Ms Burton said.

"It doesn't matter if she's eating or foraging or sitting upright, baby's being held nice and close."

Senior primate keeper Damien Lewis said the baby's father Otana, or Otty, has been curious about the newborn.

"Otty's behaviour around Kimya is really interesting because she'll go: 'I want you to come close, come close, no, too close! Back off!'" he said.

"She's certainly controlling the situation between him and her."

The keepers will compile a list of five potential names for the new arrival, which will be put out for the public to choose.

The gorilla enclosure will open to zoo members on Thursday ahead of limited public viewings from Friday.

"Visitors, when they come in, I'm sure their hearts will melt as ours have," Mr Lewis said.