The woman says she was flagged for additional screening at the Lihue Airport Wednesday because of her electric breast feeding pump.
She claims agents told her she couldn't take the pump on the plane because the bottles in her carry-on were empty.
"I asked him if there was a private place I could pump and he said no, you can go in the women's bathroom. I had to stand in front of the mirrors and the sinks and pump my breast in front of every tourist that walked into that bathroom. I was embarrassed and humiliated and then angry that I was treated this way.
When the bottles were full, she was allowed back on the plane.
The TSA is apologizing, saying the agent made a mistake.
The agency released a statement, saying in part: "We accept responsibility for the apparent misunderstanding and any inconvenience or embarrassment this incident may have caused her."
The TSA recently changed screening procedures to allow women to carry breast milk onto planes without testing it.
However, breast pumps may require additional screening.