"The children were absolutely delightful. They made a tremendous effort to welcome us to the area and we, in return, wanted to give them our help and support," Mr McManaway said.
"It's the nature of the PPP Group to dig deep and support rural communities and we are all thrilled that we raised so much money for the school.
"It is a good feeling for us to leave a positive footprint after visiting this stunning area."
The impromptu auction raised $41,500, which was presented to the school on Thursday and pupils had since created a thank you video for the group, describing how they will spend the money.
Some of the money will go toward installing heat pumps in two classrooms and upgrading the school Wi-Fi system to ultrafast broadband and to buy new kapa haka uniforms.
Mr McManaway founded the PPP group in 2005 as a means of "building an agricultural bridge across the Tasman to encourage high level debate around issues affecting both New Zealand and Australia".
He said the group has now grown from a handful of members to more than 130 of "Australasia's most influential agri-professionals" -- representing 12 million hectares (28 per cent) of farmland across the two countries and more than 20 million livestock units.