NATURE will take its course in coming weeks, with a little human intervention, and hopefully turtle hatchlings will break through the sand at three local nesting sites, avoid predators and reach the sea.

Since the rare discovery of green sea turtle nests on Boambee Beach, south

of Bonville Creek, and another at Yuraygir, National Parks and Wildlife Service has been helped by volunteers from Jetty Dunecare, Bundagen and Minnie Water to fence off the nests to protect the vulnerable species.

Next Tuesday will mark 80 days since the green sea turtle nest on Boambee Beach was discovered, which means it is time to start monitoring the nests for the arrival of hatchlings.

Turtles emerge 85 to 100 days after eggs are laid.

"We are gearing up to start monitoring the nests more regularly to see if we have got any hatching activity," NPWS ranger Ann Walton said.

"There will be extra monitoring of the sites and a host of volunteers have signed on and are checking the nests regularly, testing sand temperatures."

For sea turtles, sand temperatures are paramount to survival.

Ms Walton said temperatures must stay above 19 degrees for a nest to go full-term, while temperatures would also dictate the sex of hatchlings.

The magic mark is said to be 27.8 degrees. Above that produces females and below that males.

The rare Coffs Coast nesting sites, which have stayed around 24 degrees, are destined to produce male hatchlings, unlike many Queensland nests, which after above-average late summer temperatures will produce female turtles.

Ms Walton said multiple green sea turtle nestings appeared to be cyclical on the Coffs Coast, occurring every seven to 10 years.

"Sadly a lot of nests end up inundated by the surf and never hatch," she said.

"We are thinking two of these three nests have remained protected, but the Boambee Beach nest is only about 10-20 metres from the high water mark.

"Despite the effort to protect the site, all the reinforcement work, the sand bagging during big seas and the building of trenches we are concerned there may have been some seepage into the nest during the large southerly swell that we saw in the first week after the nest was discovered.

"I have to say the public have been fantastic.

"There has been a lot of concern shown for that particular nest given the beach is popular with 4WDs, horses and is a leash-free dog beach."

With hatchlings easy pickings for predators, only about one in 1000 turtles are estimated to survive into adulthood but in Coffs the hopes are high.

"What will stimulate the hatchlings to emerge is usually a drop in temperature so expect the hatchlings early in the morning," Ms Walton said.