GFJ NZ Seal, Image & Found by Xaalaax.
Found in New Zealand, ?mm.
GPO / NZ // NA? / 847
From the finder, 'Has "GFJ NZ" and "847" on the back.
Appears to have Nm above the 847.'
From Mudwiggle, "This is actually GPO NZ used for mailbags. Number references the particular Post Office, although I have as yet been unable to find any register that details particular locations/regions with their numbers."
"The New Zealand Post Office was a government department of New Zealand until 1987. It was previously (from 1881 to 1959) named the New Zealand Post and Telegraph Department (NZ P&T). The New Zealand Post and Telegraph Department was renamed the New Zealand Post Office in 1959. ... On 1 April 1987, the department was abolished under the Postal Services Act 1987, and three state-owned enterprises (SOEs) were formed, responsible to the Minister of State Owned Enterprises, initially from 14 August 1989 Stan Rodger."