Stem cells, skin, red blood cells and platelets are all frozen in liquid nitrogen freezer at the New Zealand Blood Service for later use - but not whole bodies.

Cryonics, the practice of deep-freezing bodies, remains a controversial area of research with many scientists in New Zealand reluctant to wade into the freezer.

Not surprisingly, the art of filling the deceased with antifreeze, suspending them in liquid nitrogen in the vain hopes that scientific break-throughs will one day reanimate them and cure them is not an accepted academic discipline New Zealand, and therefore isn't pursued in any official capacity.

But that hasn't stopped a few individuals from trying.

CHRIS MCKEEN/FAIRFAX NZ Dr Richard Charlewood, is the medical director of the national tissue bank, run by the New Zealand Blood Service.

Two New Zealand foundations -The Foundation for Anti-aging Research and the Foundation for Reversal of Solid State Hypothermia - were given the cold shoulder in 2013 when applying to be considered a charity from the Charities Registration Boards (CRB).

READ MORE: Kiwi's body hangs upside-down in a -196C vat

The board rejected the foundations on the basis that cryonics was not an accepted academic discipline based on the lack, in mainstream science, of feasibility and benefits of the research.

This decision was then successfully appealed in october 2016 - when Justice Rebecca Ellis found cryonics research to fall squarely under the 'advancement of education' heading and therefore had 'charitable purpose'.

She said there was evidence that the proposed research was likely to lead to advances in areas such as organ transplant medicine, stem cell research, and treating a range of diseases and disorders.

The listed officers and trustees for both foundations have addresses Monaco, Switzerland and Liechtenstein.

Others, Saul Kent and William Faloon bought an old church in downtown Hollywood in 2013 for $880,000 and founded the Church of Perpetual Life.

The pair are big were the cryonics world and both personally signed up for their shot at eternal life.

Nothing has been heard from the foundations since the CRB appeal and all attempts to contact the trustees were unsuccessful.

The closet thing that happens to freezing humans in New Zealand is cryogenically freezing tissue through the tissue banks of the New Zealand Blood Service.

Stem cells, skin, red blood cells and platelets are all submerged in a cryoprotectant and frozen to liquid nitrogen temperatures of around negative 196 degrees Celsius - for later human use.

"The skin cells last for up to 5 years, and stem cells up to ten years," said Richard Charlewood, the national tissue bank's medical director.

"We don't like keeping it for any longer than that because most of the studies only go up as far as ten years.

"At liquid nitrogen temperatures very little is actually happening at molecular level. So it's possible that they would be fine well beyond ten years, we just don't know for sure."

Charlewood said when cryo-preserving, the key thing is to get the cryoprotectant into all the cells that you want to keep alive, otherwise the formation of ice crystals can burst the cells and kill them.

"In terms of whole body freezing, my understanding is that you have to get the cryo-protectant to all the cells in the body, so you'd have to pump it around the body really thoroughly."

Fertility specialists in New Zealand also offer cryogenic preservation of eggs, ovarian tissue, sperm and embryos for reproductively-challenged patients who wish to conceive later.

Otago University's associate professor in botany, David Burritt, also regularly employs cryopreservation in his line of study.

In a 2016 research paper he said cryopreservation was a great method for long-term storage of reproductive plant material - such as seeds, pollen, dormant buds, shoot tips, embryos, or isolated plant cells or tissues.

"Plant material is first preconditioned, using chemical and physical treatments, so that it remains viable when it is frozen and during ultra-low temperature storage."

"Following re-warming, seeds and embryos can germinate, buds or shoot tips can be induced to grow, and whole plants can be regenerated from cryopreserved cells or tissues."

He said the samples could, in theory, be conserved indefinitely as "no metabolic activity occurs at these ultra-low temperatures."

'Cryobanking' enables large numbers of important crops, such as wheat, potato and various fruit and forest trees, to be cryopreserved, rewarmed and then allowed to grow into complete plants.

In March, scientists in the UK succeeded in cryogenically freezing and rewarming sections of heart tissue for the first time, in an advance that could pave the way for organs to be stored for months or years.