You Do Need power plug adapter while traveling from Syria to Niue.

Here is Why You Need An Adapter

The outlet and plug type used in Niue is I and in Syria are C, E and L. This is how they look like.

Syria

In Syria, outlets of type C, E and L are in use.

Type C

Type E

Type L

Niue

In Niue, outlets of type I are in use.

Type I