The most common and most likely answer to this crossword clue is the 6 letter word TAHITI
I've seen this crossword clue in The Daily Telegraph
T
A
H
I
T
I
More clues leading to the result TAHITI
- Island thanks island, after success
- Island volunteers arrive at island's capital
- Note about a popular song in S Pacific island
- Army volunteers successfully attacked island — one in the Pacific
- Volunteers having success on one island
- Island battered in conclusion, briefly
- Island that rises round one Polynesian paradise
- Reservists strike unit on Pacific island
- Island that gets confused with two small islands
- Isle that rises to enclose one Pacific paradise
Buddy explains!
The straight part
We know that "one in the south Pacific" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one in the south pacific = tahiti.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.