The licencing of patents relating to radio manufacture prior to 1934 was not particularly well managed in Australia and New Zealand, and licence fees here in NZ (such as they were) were paid by the government at the rate of 3 shillings from each radio licence fee.

In early 1934 the Australian Radio Technical Services & Patents Co. Ltd (ARTS&P) was formed by the patent holders, issuing a single manufacturing licence and allowing applicants on both sides of 'the ditch' to use any patents. ARTS&P also provided technical assistance to manufacturers so they could make the best use of the patented technology they were paying for.

The licencing system was introduced on July 1, 1934 and was, at first, not well understood. An article in the ODT in the 28th of June 1934 explained that owners of radio patents receiving payment for their technology when a radio set was sold was similar to an author being paid royalties for the sale their book.

1934/35 ARTS&P Label

The licence was on the basis of 3 shillings and sixpence per cathode electron stream in the set (not the number of valves, although often the two were the same) and this number is found in the top left corner of the label.

In the first year (1934) labels in NZ were printed on white paper and stuck on (while Australian 1934 labels were plastic and riveted to the chassis).

1935-1946 ARTS&P label
see below for details
From 1935 until 1946 the labels were all pale blue, although the year can generally be approximated by the letter prefix on the labels serial number (which did not bear any resemblence to the radio serial number). From 1946 the licence labels changed color a few times, and this allows modern collectors and enthusiasts to at least ball-park age their sets if no other identifiers are available.
1946-1950 ARTS&P label

1950-1951 ARTS&P label
While this system was used in Australia and New Zealand, there were some subtle differences between the two countries - most notable the wording, which either refers to the Commonwealth of Australia or the Dominion of New Zealand

1952- last ARTS&P label
The final label issued was blue and smaller than the previous labels (most likely because sets were becoming smaller, and real estate on a chassis was getting harder to find), but the use of this licensing system died out in the 60's and its common to find no trace of a label ever having been fitted to radios from the mid-50's on.

Label Identification

1934   White newsprint label, serial number has no prefix (white plastic label, 'A' prefix in Australia)
1935-1936   Serial number prefix 'B', pale blue label
1936   Serial number prefix 'C', pale blue label
1937   Serial number prefix 'D', pale blue label
1938   Serial number prefix 'E', pale blue label
1939-1940   Serial number prefix 'F', pale blue label
1940-1941   Serial number prefix 'G', pale blue label
1942-1946   Serial number prefix 'H', pale blue label
1946-1950   Dark green with red letters, serial number prefixed by the letter 'I'.
1950-1951   Orange with dark green letters, serial number prefixed by the letter 'I'
1952-1960s   Small pale blue, with dark blue letters, no prefix to the serial number.

Note, the dates above are not hard and fast. Particularly with the dark green and orange labels which often appear to have an overlap of several years - some green labels being seen as late as 1952, by which time the new small blue labels had begun to appear. Also, a lot of sets just post war do not seem to have labels at all - this could simply be because production of domestic radios had shut down for several years to focus on the war effort and they weren't immediately available. By 1946/47 labels were in regular use again.

Information was gathered from various sources to produce this list including scanning of hundreds of radios for dates and labels:
More Golden Age of Radio - John W. Stokes
The Otago Daily Times, 28 June 1934