In te Reo Māori, Kaiāwhina translates to helper, assistant, contributor, counsel or advocate.
Sharni says the new service will fill a huge gap in the Te Awamutu community.
"There are often pockets of women who are falling through the cracks of our health and social care systems," she says.
"These women don't have good family support, little or no parenting skills or knowledge, anxiety, birth trauma or postnatal depression," Sharni says.
"They might be young mothers, solo mothers or just mothers who require care and guidance."
Kaiāwhina will help with anything from folding washing and cooking to holding the baby while the mum has a shower or nap.
Sharni says a Kaiāwhina is like a New Zealand version of a doula.
A doula is a non-medical companion who supports a new mum, or mum-to-be, by providing care before, during, or after childbirth in the form of information, physical help and emotional support.
A Kaiāwhina does not take the place of a midwife, but works alongside them.
Sharni says the role a Kaiāwhina plays has been performed since ancient times, when a village of helpers surrounded a new mother with care during the special days and weeks after giving birth.
"But these days it's common for a woman not to have that community of support if they do not have close family, friends, neighbours or a group, such as a church, to lean on."
Sharni says many new mums quickly become part of social media groups, parenting forums and mum groups.
"While these groups can be helpful for some mums, they can lead to comparison and feelings of inadequacy for other women."
A Kaiāwhina's purpose is to support and uplift a mother, depending on her needs.
The confidential service will be available for mothers in the Te Awamutu, Kihikihi and Pirongia area referred by local midwives.
The Kaiāwhina volunteers will be handpicked for their passion for seeing mothers flourish.
They will be trained in first aid, mental health and for a range of situations including breast-feeding support, cultural safety and basic massage for a mother and baby.
The volunteers will initially be unpaid, but Sharni hopes they can be funded in the future.
Kaiāwhina falls under the umbrella of Loving Arms NZ, a community organisation Sharni founded five years ago that provides baby clothes, products and furniture to new mothers and babies in the Waipā district.
Sharni received a local hero medal in 2016 to acknowledge her efforts running the organisation.
Last year the service was the regional winner of the Trustpower Waipā Taupō Regional Community Awards.
Sharni is also a maternity consumer representative for the Waikato DHB's maternity quality and safety programme.
MP for Taranaki King Country Barbara Kuriger said she was in awe of Sharni.
"I have watched Sharni working tirelessly and passionately in her local community for the last five years.
"Kaiāwhina is an incredible initiative that will change many lives and hopefully inspire others to take steps towards supporting new mums."
National Party deputy leader Paula Bennett said she was inspired meeting Sharni and hearing about the initiative.
"There are a lot of people in this world that are talkers and there are those that take action. It's exciting to see that someone has identified a need and taken action."
"I believe the best thing we can do for children is to actually take care of the mothers, to empower mothers to take care of their babies best."