The team ended up catching 51 koalas, 25 of which are females and the other 26 males, which is more than the group were hoping for.

They had been scouring properties around Wandobah State Forest and on Millroy Road for koalas, and at the beginning of their visit to town, found much less than usual.

Fifty of these cuddly creatures will be used for the trial, as the last one was in "very poor body condition" according to zoologist Dr Valentina Mella.

"We didn't want to put him under stress. You never know, if he has a bad reaction, if it's due to the vaccine or due to not being well," she said.

"We don't want to want to do anything bad so we just excluded animal."

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The vaccine has been developed using samples from koalas in the Gunnedah area and is being administered to sick and well koalas to both combat and prevent the disease.

"It's a very nice vaccine because it doesn't just have protection but it also has curative properties so that means if an animal is already sick or already has chlamydia, some of these signs can get better with the vaccine which is really important," Dr Mella said.

"We need to see how long it lasts. We know it works but does it only last a month? Two months? Three months? This becomes really difficult to make it a useful tool. You can't go out and vaccinate animals every two months."

The team is now back in Sydney, where they will go back to the lab to look at the samples they've collected.

Dr Mella said the real answer for their questions would come in about six months time, when they return to Gunnedah and see what's happened while they've been gone.

But she said it was very important for locals to get in contact with the team if they saw an injured or diseased koala with a collar on.

"It would be really fantastic if any landowners see one of those koalas in danger near the road or after its been hit by a car to please let us know otherwise ... we don't get a signal anymore for that collar and we don't know what happened."

They can get in contact by emailing valentina.mella@sydney.edu.au

The zoologist encouraged any landholders in the area who might also want to set-up a Tree Troff water station to register their interest, too.

"It would be great to have a few more landowners who are happy to set up these water stations for these animals," she said.

"Droughts are just around the corner, the weather is not getting any better."

The drinkers encourage koalas to venture out and have a big sip of water.

They can sign up for a free Tree Troff via https://www.wires.org.au/water-for-wildlife