You may try out the online tests here to find out if your child might have symptoms similar to ASD.
This is not an official diagnosis for autism.
For an official diagnosis, book an assessment from the various centres here.
Seek advice from your developmental paediatrician if you observe the following:
Lack of eye contact
Delayed speech or language skills
Poor imaginative play
Solitary - shows little or no interest in interacting with others
Your paediatrician will not be able to diagnose your child, but he/she will be able to arrange for necessary assessments and work together with a multidisciplinary team of specialists to determine if your child is at risk of autism.