A stepmum blamed Australia Post for abandoning her children. But they've had the last word.

Australia Post has responded to the Perth stepmother, who allegedly left her young children alone at home to fly to Bali.

The 28-year-old reportedly blamed Australia Post for leaving the children aged four and six behind because their passports had not been delivered in time.

A spokesperson for Australia Post told WA Today the responsibility of delivery sat upon the shoulders of the Chinese postal office once it had cleared their borders.

“Delivery of this item in China is the responsibility of China Post once the item has been cleared by Chinese border authorities,” he said.

The children were found by police last Wednesday in a house that was left unlocked and taken into state care.

The father of the children was also said to be overseas at the time of their alleged abandonment.

Watch the Channel 9 coverage of the report. Post continues after video...

The woman was interviewed by Nine News and relayed her concerns for her children through an interpreter.

"Of course I am very concerned about them," she said. "That issue is between myself and the children.

"If you're really concerned about my children can you please help me sort out this post office and locate the passports? Without passports my children will not be legal here."

It was reported Australia Post said the package had been successfully dispatched from Australia on December 15, bound for China.

A neighbour told The West Australian she heard the children were distressed but didn't realise they'd been left behind.

"The kids were crying and screaming," she said. "Had I'd known I would have called the police."

The children were left unsupervised for two days before they were found by police.

The woman was charged with two counts of knowingly engaging in conduct that may harm a child in her care when she was arrested upon her return to Perth on Thursday.

The father reportedly remains overseas.

Feature image via Channel 9.