You Do Need power plug adapter while traveling from Saint Martin 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 Saint Martin are C and E. This is how they look like.

Saint Martin

In Saint Martin, outlets of type C and E are in use.

Type C

Type E

Papua New Guinea

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

Type I