Minted in New Guinea, these coins are almost identical except for size and the number of points of the star on the back: 3 pence has 4 points, 6 pence has 8 points. Catalog values for all dates of 3 and 6 pence are virtually identical as well:
worn: $2 US dollars approximate catalog value
average circulated: $4
well preserved: $12
fully uncirculated: $25
The 1945 6 pence is slightly more valuable than the other coins. It catalogs near $15 in well preserved condition.