The tough coastal walkway he will cover with running buddy Tom Bland includes 35,000m of ascent and descent. That's the equivalent of going up and down Mt Everest four times. Or put another way, that's to the top of the Sky Tower and back 13 times a day for the two week duration.
Law says he gets an enormous buzz out of thinking up and planning his challenges.
"I guess my way of thinking is that if I'm going to be doing that then it would be morally incorrect not to use that same passion and that same drive to try do a little bit of good in the greater world," he says.
Having a fundraising goal also helps Law with the motivation for the training, which usually involves long hours squeezed around his other commitments.
Law shares his top tips for helping others benefit from your running:
* Run for a cause you have a personal connection with
"I've chosen causes that have a deep significance to me personally and I guess that makes the motivation I get from that that much stronger," says Law.
Law's support for the leukaemia charity comes from having lost his brother, Alan, to the disease. During the 7in7 runs he carried a picture of Alan at all times, which he found helped enormously with motivation.
His fundraising for the Mental Health foundation has the same personal link.
"Rather tragically my brother-in-law took his life after a long battle with depression. I was the one unfortunate enough to find him."
Choose to support a charity associated with something that has affected your life so that when you talk to people about it they are more sympathetic to your motivations for fundraising, he says.
* Promote yourself shamelessly
There is only so much money you can tap your family and friends for so the fundraising net will need to be flung wider.
Law says he isn't someone who is naturally comfortable with putting himself forward or asking people directly for money.
"It feels kind of like a cold-sales call but you've just got to overcome that hurdle and get a little bit shameless."
* Get hooked in to social media
Law says he has become adept at blogging and using social media to help get the word out about his charity runs.
"There is just no doubt at all about the power of those when it comes to something like doing a fundraiser."
He says to start the campaign six months to a year in advance to gradually build up a community of interest of people who are following you on Facebook or through a blog.
"The whole aim then becomes one of engaging the audience in your story and your journey," says Law.
People then become so caught up in the story and have been entertained, inspired and informed enough to donate some money, he says.
* Give something in return
Law says another trick for good fundraising is to find as many ways as possible to give people who donate something back in return.
If he's making up t-shirts for supporters Law will often make up some extras to sell in exchange for a donation.
For anyone wanting to support Law's fundraising or simply keep up-to-date with his run then check out the Coast Path Run Facebook page or website.
With around 550 people committing suicide each year in New Zealand - that's double last year's road toll - his fundraising cause is likely to resonate with many.
Events:
* Now in its 48th year, Rotorua Marathon competitors run 42km around Lake Rotorua on Saturday April 28.
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