"I fronted up at the desk and they said they didn't have any record of my name," Benny said.
After some quick work from games organisers her registration was completed she was competing the next day.
Benny is a regular NZMG competitor, having competed at Dunedin (which hosts it every second year) five times and the World Masters Games in Auckland in 2017.
She also won gold in the open water swim at the FINA World Masters Games in Perth in 2008
"But I've never been to Whanganui before, first time here," she said.
Benny has competed in the 44km road cycle, 1km and 500m indoor rowing, 50m backstroke and 100m freestyle pool swim.
So far she's claimed three gold medals with more pool events and the open water swim. to go.
While in Whanganui Benny has checked out tourist spots such as Bushy Park, Bason Botanic Gardens, Kai Iwi beach and the Sarjeant Gallery.
"Love it. I'm really impressed," she said.
She said masters events were important for people getting into sport and off the couch.
"I just think it's hugely motivating,' she said.
And despite the near mishap, Benny said she was keen to return to Whanganui for another Masters Games.
"I won't have that senior moment next time."