Three six-week-old male lion cubs at Werribee Open Range Zoo have passed a health check with flying colours.

It is the first time the zoo’s veterinary staff have been able to get close enough to examine the sex of the cubs since their birth in October.

They have had a strictly “hands off” policy when it comes to taking care of the cubs, leaving all of the work to mother Nilo, zookeeper Katherine Quinn said.

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“We want them to behave like lions so we’ve been hands off,” she said.

“Now we’re at the point where we needed to go in they needed their vaccinations.

“They certainly didn’t enjoy getting a needle but nobody does.

“We were able to give them a good looking over and let them get back to doing what they do best, which is being lions.”

Watch the cubs’ health check here

The cubs have been living in a den with their mother away from the other animals since their birth.

The mother was sent outside while vets weighed and microchipped the cubs and checked their general health, senior veterinarian Dr Natalie Rourke said.

“The cubs passed with flying colours,” she said.

“Their mother’s doing a brilliant job. Their body weights are just under seven kilos and they’re growing terrifically.

“Their growth rate is perfect. We’re looking for visual acuity. They seem to have no problem with that and of course we’re interested in their cardiovascular system. But they’re all clear.”

Once the cubs are introduced to their father and aunty, and are comfortable with them, they will be released into the outdoor area.