New Zealand Volunteers
According to https://www.jsmilitaria.com/nz-vol-badges.html volunteer corps helped in the local defence of New Zealand from the early 1840s through to the second Boer War.
Backmark: Smith & Wright Birmh Although this button was purchased in Australia, the same design was used by some NZ volunteer units between 1866-1909.
1870 pattern NZ Rifle Volunteers. Backmark: Ross & Glendining, Dunedin NZ
1882 pattern NZ Rifle Volunteers. Backmark: The New Zealand Clothing Company.