Australian couple deny claims they abandoned baby Gammy

The surrogate mother of abandoned baby Gammy in Thailand has identified a couple from Western Australia as the boy's parents.

Pattharamon Chanbua, 21, said the biological parents took the boy’s twin sister back to Australia but left Gammy, who has a congenital heart condition and Down syndrome, in her care.

9NEWS spoke to the couple identified by Ms Pattharamon and they confirmed they do have a baby daughter of a similar age to Gammy, but denied that she has a twin brother.

The pair admitted using a Thai surrogate, describing the experience as "traumatising".

Baby Gammy is currently being treated in a Bangkok hospital for a serious lung infection.

Ms Pattharamon has since vowed to look after Gammy as her own.

She told Fairfax Media yesterday that the biological father "came to hospital to take care of the girl but never looked Gammy in the face or carried him".

The six-month-old was relocated to one of the most advanced hospitals in Thailand after initially being treated in a hospital in Chonburi province in the country's southeast.