Competitors have to maintain an average of 96km a day, which is more than two marathons.
The race starts daily at 6am and runners can continue to midnight when the course closes for the day.
Davies, a member of the national Sri Chinmoy Marathon Team, is the only Kiwi woman to ever attempt this challenging distance.
By day 43, on Monday, she had completed 4184km, meaning she has a high chance of reaching the 4988km before the race finishes.
"Many of us go through life wondering about what we might have done if we had dared to attempt something daunting and difficult," Davies said.
"[The distance] really frightened me, but I decided to venture into that frightening place and challenge myself and see what I could learn. It's one of the best and happiest and most amazing experiences I have ever had".
Day 27... from Perfection Journey Films on Vimeo.
She has suffered a few aches and pains along the way.
"There is always going to be something wrong. There is always going to be a pain here or an ache there. Feel like you're getting a stomach virus. So I am learning to accept that and be okay with that. They make you stronger.
"It's an incredible lesson for life that you can't be affected by obstacles.
"I am really not trying to think about the whole distance. That is really hard. Your mind just wants to constantly think about how many more days, how many more miles. As soon as your knee gets sore you think 'How will it ever be possible to do 20 more days'. My mind is constantly wanting to look into the future like that."
Only six women have completed the race in the previous 20 events, with only one other New Zealander ever attempting the challenging epic journey.
The race was founded in 1997 by the late Sri Chinmoy, who pioneered many long distance events and has been credited with reviving multi-day racing.
The marathon team he founded hosts New Zealand's national 24 hour championship race, and over 30 road races and marathons annually.
Sri Chinmoy was a great believer in humanity's potential - a philosophy he called "self-transcendence" - and made headlines over 20 years ago when he predicted that the sub two-hour marathon mark would fall in the coming few decades.
His prediction almost came true recently when Kenyan marathoner Eliud Kipchoge, gold-medalist at the Rio Olympics and the best marathoner in the world, stepped up to the starting line at the Autodromo Nazionale Monza race track in northern Italy and ran the fastest time ever recorded - 2 hours and 25 seconds.
You can watch an interview with Harita Davies above after she completed 2494km, a total nearly three times further than she had ever run.