Baby girl dies in hospital days after twin's death

The twin sister of a baby girl who died at a Brisbane home has also died in hospital.

Police and paramedics were called to the home at Sunnybank Hills on Wednesday where one of the six-week-old pair was confirmed dead.

Her twin was transported to hospital in a critical condition, but police say she died last night.

Their deaths are not being treated as suspicious.

Preliminary investigations suggest the babies were sleeping together throughout the night and were discovered unresponsive in the morning.

A report will be prepared for the coroner.

On Wednesday, an unnamed neighbour said she was woken by an ambulance and she heard the father "howling" for hours afterwards.

"He was howling and screaming," she said.

"I thought someone was dead and it really scared me. He was so upset."

Family friends have set up a fundraising page online, and have raised more than $2,500 in 12 hours.

Of the organisers, Kieran, told 9News.com.au the family is "devastated".

"We just wanted to set something up to help in some way," he said.