The first involved two men and happened on Scotter Road at around 10pm on Friday.
Officers want to speak to a man walking his dog in the area at the time who may have seen it.
The second alleged assault happened a shortly after on Shakespeare Avenue. It was reported that two men and a woman assaulted a man.
Officers think another lady witnessed the incident and spoke to those involved.
Two men and a woman have been arrested in connection with the incidents. All three have been released under investigation.
Anyone with information is asked to call 101, quoting investigation 16/35383/18.