"I heard when they left they were angry boys," she said.
That was when she heard someone mention coming back with "something" to "deal to it".
She did not hear or witness the shooting.
A woman at the house the party was held at refused to comment.
She said she was asleep when the shooting happened.
Several nearby residents said they spotted a brawl break out in the street earlier in the evening, with people "tackling" each other. One person estimated more than 10 people were fighting.
Another woman said she and her family did not feel safe in the area, and that there were always police showing up.
Police have not commented on the party or alleged fight.
The incident comes just a few months after another shooting in Stokes Valley, which was the result of a "family harm incident", according to police.
Lower Hutt mayor Ray Wallace, who is in Japan at the moment, said the latest shooting was an "isolated incident and not the norm".
"I am in Stokes Valley often and it has a great community spirit and council's recent investments with Koraunui Stokes Valley hub its having real positive impacts for the community so this is out of character for the majority of Stokes Valley.
Police are currently investigating the shooting incident and have said "there are no threats to public safety".