The children were born in NZ darian. I will add a little more so someone else may recognise the family and photo. Like you, I have not found them living in the South Island. They may have holidayed there or James Ring may have been a roving photographer for awhile.

John Hendry Cameron (1881-1925) was born in Queensland.
Constance McGarvey (1885-1957) was born in Whakatane, 1 of about a dozen children of Daniel Cornelius Francis 'Dan/Frank' McGarvey (1856-1926) & Jane Elizabeth Sellars. Dan was also born in NZ (Auckland) and had stores on the East Coast, Tauranga, Opotiki, Te Teko and Whakatane where he was one of the pioneer settlers.
John & Constance married in 1905 & had at least 6 children
born in Whakatane ..
1906 - 1956 John Sellars Cameron
* married Kathleen Vera Dunckley in 1933
1907 - 1961 Muriel Mary Cameron
* married Frederick George Ryan in 1929
1909 - 1960 Heather Cameron
* married James Stephen Ryan in 1929. When she became engaged to James in Jan 1929, Constance was living at Hopper St., Mt Cook, Wellington.
1911 - 1970 Ivan William Cameron
* Ivan married Brenda Warner-O'Leary in Sydney 1932 & is buried Macquarie Park, Sydney
1914 - 2011 Winifred Frances 'Winnie' Cameron
* Winnie married Basil Raymond Potton in 1935. She died in Cleveland, Queensland aged 97
1919 - Mary Cameron

John Hendry Cameron died in Wellington Hospital 20 July 1925 aged 44
Constance died 11 Aug 1957 in Wellington aged 71

So you reckon I've got it then.

I should have placed the link to the auction as the item is currently for sale and shows James Ring's mount of the time.

https://www.trademe.co.nz/a.aspx?id=2631177407&tm=email&et=41&mt=3B9681F4-EFDD-45D4-BC17-7F5CA3ADC250

Another researcher said it is definitely an Edwardian mount, 1901-1910 also fitting in with the birth dates of the Cameron children.

Thanks for the extra information. It lines up with everything I found as well. And I like the 'holiday' theory. It was not unusual for people to get portraits done on trips away. It's possible they were visiting some other Camerons down that way.

Your welcome Darian
Pleased to sort it for you.

Are you buying the photo?