A Cloverdale stepmother has been charged after allegedly abandoning two children at their home for three days to travel overseas.

Police said the children, aged four and six, were found alone at the Cloverdale home when officers gained entry through an unlocked door on Wednesday.

It is alleged the woman, 28, left the children at the residence the day prior to fly out of Australia.

The woman arrived back in Western Australia on a flight on Thursday and was detained and arrested at Perth International Airport.

"It will be alleged both parents were overseas at the time the officers entered the property," a police spokeswoman said.

"The children were subsequently removed from the property and placed into appropriate care."

Police said the woman was in a de facto relationship with the father of the children, and is not their biological mother.

The father is believed to have been elsewhere overseas.

The woman has been charged with two counts of engaging in conduct which could result in harm to a child in a person's care and control.

She will face court on June 22, and police said inquiries into the matter were continuing.

Child Protection Minister Andrea Mitchell said the children were now receiving appropriate support from authorities.

"When I first heard about this situation I was horrified," Ms Mitchell said.

"Any incident where children of any age being left alone is extremely concerning."