The charity wants to create a sensory-friendly space for children with complex and life-limiting conditions, neurodiverse patients and families receiving end-of-life care.
Around 10,000 children and young people receive care through the Children's Unit each year, according to NorthCare Charity.
The charity said some children spend weeks or months in hospital, with parents and other family members spending long periods on the ward with them.
Money raised through the appeal would be used to provide specialist sensory equipment, new lighting and improved facilities in the Sunshine Room.
Plans also include dedicated accommodation space for parents and siblings.
NorthCare Charity said the room would be designed to provide a calmer environment for children with complex needs and give families more space while their child is receiving treatment or end-of-life care.
The charity is seeking support from communities, businesses, schools and other donors in Oldham and across Greater Manchester to reach its £250,000 target.
