You Do Need power plug adapter while traveling from Denmark to Papua New Guinea.

Here is Why You Need An Adapter

The outlet and plug type used in Papua New Guinea is I and in Denmark are C, E, F and K. This is how they look like.

Denmark

In Denmark, outlets of type C, E, F and K are in use.

Type C

Type E

Type F

Type K

Papua New Guinea

In Papua New Guinea, outlets of type I are in use.

Type I