The most common and most likely answer to this crossword clue is the 8 plus 6 letter word PITCAIRN ISLAND
I've seen this crossword clue in The Times
P
I
T
C
A
I
R
N
I
S
L
A
N
D
More clues leading to the result PITCAIRN ISLAND
Buddy explains!

The straight part
We know that "S Pacific territory" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case s pacific territory = pitcairn island.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.