It was then that the 74-year-old fell and lost consciousness, dying later that evening in Auckland Hospital.
A national contract manager for Ritchies, Matthew Todd, said the company felt devastated by what had happened.
"Ritchies is devastated by the incident that occurred on one of our services on Friday, our thoughts and prayers are with the family and friends of the passenger involved in this terrible event," Todd said.
"Ritchies is working closely with WorkSafe and the NZ police in their investigation. We will not be making further comment until the relevant authorities have completed their inquiries."
A teacher, Kelly Clark, who was on the bus previously told the Herald that she had heard a huge noise and had gone to help the woman.
"I heard a large bang so I went down to see what it was... I had a feeling it was someone who had fallen down the stairs," she said.
"We hadn't even really moved ... we hadn't moved out of the bus stop."
Clark, alongside two other young women, put Johns into the recovery position.
"She was never conscious," she said.
They looked after her as best they could while they waited for the ambulance, she said.
Clark said it was sad to hear of Johns' death.
Acting Senior Sergeant Nick Herd, Waitemata Police, confirmed yesterday that Johns had been trying to hand in a wallet when she fell.
"This was an absolute tragedy for this woman's family and our deepest sympathies are with them during this difficult time," Herd said.
WorkSafe confirmed an initial inquiry was now under way.
Auckland Transport media adviser James Ireland previously told the Herald staff were advised of the incident on Friday and had been told Ritchies Transport was undertaking a full investigation.
"Our deepest condolences go out to family and friends affected by this tragedy."
AT would assist in the investigation, and any other inquiries or investigations in any way it could, Ireland said.
While that particular bus was no longer operating, so that police could conduct their investigation, the "double-decker services were running the same as usual".
The obituary called Johns an "amazing" woman who would be missed by all.