Robotics research in helping children with autism has gained increased attention in recent years. Children with autism often struggle with neurodevelopmental disorders that affect their lives particularly in communication skills, social interaction and their repetitive stereotyped behavior. In this article, we highlight previous findings on human-robot interaction for children with autism. To date, it has been claimed that child-robot interaction is a beneficial approach in helping children with autism to improve their quality of life. Based on an extensive search of the literature, we identified three major research gaps: (1) diversity in research focus, (2) bias contribution in robotics research towards specific behavior impairments in autism and, (3) effectiveness of human-robot interaction after robot-based intervention program. Therefore, this review paper shall identify and thoroughly discuss published works that address the research gaps found in this areas. This article is therefore seen as a crucial step in bridging the gap between robotics research and children with autism. The results presented could be beneficial for researchers in determining future directions for robotics research in helping children with autism.