This adds to the fertility of the soil structure and at the same time gets rid of the dung sitting on top of the ground.
Mr Phillips said there were many environmental and economic benefits to be had.
"By feeding on the dung, they take the dung off the surface, so there's less faecal matter and less run-off into waterways."
The beetles also improved soil fertility and soil biology by breaking down the manure.
"They create more porous soil and more nutrients in the grass," said Mr Phillips.
"They are hard workers, they move a lot of dirt."
Their hard work can increase pasture productivity, available grazing areas and water filtration.
Mr Phillips said ultimately, it meant less fertiliser and less drenching was needed.
Another benefit was reduced livestock infection from parasitic worms.
"They crunch it, squash it and bury it," Mr Phillips said.
It is estimated that animal dung covers 700,000ha of pastoral land in New Zealand.
The dung beetle field day is a joint project by Landcare Research and GWRC. It is the first release of dung beetles in the lower North Island, after the first NZ release in Gore, Southland.
The Dung Beetle Release Strategy Group is planning to release more of the beetles on to farms in other parts of the country.
Mass-rearing of dung beetles is being undertaken at Landcare Research's facilities in Auckland and Lincoln.
"They are looking at importing some more different types," said Mr Phillips.
The beetles being released in South Wairarapa are around 10mm in size and tunnel down about 10cm.
Mr Phillips said bigger beetles may be released in future.
All the beetles go through a quarantine period, breeding programme and caged field trials carried out by Landcare Research.
Permission to import and release 11 species of beetles was granted by the Environmental Protection Authority in 2011.
