Seem like a test for missile technology. Probably had a blank payload. Not sure what the issue is. It is not like it could have blown anything up.
There is no issue. None whatsoever.
However, the Sydney Telegraph is trying to make it into one.
It was to do with internal Australian and Oceanic politics
The relevations aren't as sensational as the article makes them appear. Back at the time it was known that the Australian Labor Government (which came into power in 1982) had given approval for these tests. This just extends the policy and the way it was to be handled back to the previous Liberal (that's conservative to youse Yanks) government in 1981.
Under both Govs it was "these tests are normal, but let's keep the publicity low-key as some people might be bothered"
However in 1984 NZ elected a Labor Gpovernment that made the Australian Labor Governmen look Liberal. David Lange was extreme left anti-US alliance and wanted fo be the big frog in the South Pacific pond, leading an "independent foreign policy" anti-nuclear alliance of all those other little SoPac islands.
In Feb 1985 he refused a port visit by the USS Buchanan for the alleged reason the US Navy wouldn't tell if it had A-Bombs on board.
His stance was insanely (and I use the word advisedly) popular in New Zealand and the Australian Labor Left.
Shortly after Australian PM Bob Hawke withdrew his previous agreement for the tests. At the time I (and Blind Freddie) could see that it was obvious that Hawke did that to preserve the A(NZ)US treaty alliance - already looking shakey from Lange's decision to be a non-contributing "partner". More in Bulletin of Atomic Scientists June 1985