"They're being hidden and they're living like fugitives. All they're learning is to hide and if that's what they're shown love to be, they're going to be three traumatised individuals in the future."
This is the second time the father and his children have been missing recently. Police and emergency services, iwi and community members searched for the family for 17 days in September last year before they arrived at Phillips' parents' house.
Phillips was subsequently charged with wasting police resources. His family said he had been staying in a tent in the bush. When he left again in December, police said at the time he was not violating any court orders.
However, Phillips later missed his January court appearance where he was due to face the charge of wasting police resources and police issued a warrant for his arrest for failing to show.
In her post, the sister said Phillips could be granted an amnesty "for all I care, but bring my siblings home".
"I remember watching the kids running and hiding under beds when it was time to go home. 'I want to stay with you mummy'. I imagine them asking for their mother now, wondering why they haven't seen her or any other family for so long," she wrote.
Earlier this month, another sister started a Givealittle page attempting to raise reward money for information on her sibling's location.
In the most recent Facebook post, the older sister claimed that "if child welfare doesn't speak to them maybe money will" and any remaining funds will be donated to organisations that helped search for the children last year.
So far $3285 has been raised towards a goal of $10,000, and fundraising is due to finish in early November.