(1) Section 172(1) (as amended by section 17 of and Schedule 3 to the Act of 2006) of the Principal Act is amended by substituting the following definition for the definition of "qualified parent":

"' qualified parent ' means, subject to regulations under section 177 -

(a) a widow,

(b) a widower,

(c) a separated spouse,

(d) an unmarried person, or

(e) a person whose spouse has been committed in custody to a prison or place of detention for not less than 6 months,

who is the parent, step-parent, adoptive parent or legal guardian of at least one qualified child, who normally resides with that person;".

(2) Subsection (1) shall not apply, where a person's entitlement to one-parent family payment has been established before the coming into operation of that subsection, for the duration of that person's continuous entitlement to one-parent family payment.