The senior Doctors union and the Council of Trade Unions say that $1.1 billion is required to maintain current health services which are already struggling to meet demand.
According to the Unions the figure was calculated based on data released by Government departments including Treasury.
They say the figure takes into account population growth, inflation, wages and new initiatives and comes ahead of the Budget announcement this Thursday.
YesWeCare.nz is a new coalition of community groups, patients and people working in health seeking a fully-funded health system.
Coalition coordinator Simon Oosterman says maintaining the status quo isn't enough.
“An extra $1.1b in health funding will only maintain the status quo and won't help people already missing out," he says. "It won't resolve the mental health crisis or help the increasing number of Kiwis who need surgery but can’t get on a public waiting list."
Oosterman says anything less than $1.1b will be a cut in real terms and will see more people missing out.
YesWeCare.nz has been collecting stories of people affected by health underfunding to show how it impacts everyday people.
"Every child should start life with the best opportunities," she says. "An extra $1.1b won't help families like mine who don't receive health funding but would benefit from it."
Research conducted by the YesWeCare coalition also conducted a survey of 6,000 health workers in March this year.
According to their findings 90% of respondents reported the health system doesn’t have the staff and resources required to give New Zealanders the health care they need.