The latest Ministry of Health's annual data explorer found around one in seven adults were not visiting a GP due to cost, and this figure had not changed significantly from 2011.
"It's not only the fees that can be a barrier, but also transport costs to get there," Bell said.
"Even with free doctors' visits for children under 13, if there's no car, no petrol and no bus money, it's near impossible for some whānau."
Bell said children from the most disadvantaged communities were twice as likely to end up in hospital for medical conditions and three times more likely to be hospitalised for respiratory conditions compared to those from advantaged communities.
The organisation is pleading for those more fortunate to dig deep and donate to its Winter Appeal launching today to ensure they can provide services to the 120,000 people who use it a year.
"Our work will not let up in the coming months as people continue to struggle with keeping the house warm and food on the table."
The Salvation Army Winter Appeal runs from July 8 until the end of the month and people can donate by visiting The Salvation Army website.