Dutch company Shell holds the majority of the licence to extract gas and condensate (light oil) from the field, which in its heyday produced 90 per cent of New Zealand's supply.
Mr Lester's official job title is "Person in Charge" or PIC - he's top dog on Maui A. It's a big responsibility that he likens to running a hotel while ensuring enough gas is produced to reach the company's weekly target.
Fourteen wells have been drilled from the platform, some as long as 6km. A 50cm thick stainless steel underwater pipeline transports hydrocarbons to the Oaonui production station, before gas is is sent north along the Maui pipeline, which heads to Huntly.
Sitting inside Mr Lester's small, grey office, I'm made to watch a health and safety video, sit a health and safety test, and am lectured about health and safety. Mr Lester says he meets every person who comes off a helicopter to give them the "empowered" talk - even those who have worked on-site for years.
I then don a pair of orange overalls, steel-capped boots, safety goggles, a hard hat and earmuffs for a tour of the six-level structure. That's what I think. Instead, I find myself wriggling into a life jacket before gingerly lowering myself into a lifeboat hanging off the side of the platform at a precarious angle about 20m above the churning sea.
Health and safety rules mean I must know how to get off the platform in an emergency. I get into one of Maui A's two lifeboats, belt myself in and strap my forehead to the headrest. Once Mr Lester is satisfied I know what to do, I'm happy to get back out again.
Evidently, Maui A's operator Shell Todd Oil Services (STOS) takes health and safety seriously. Before I could even place a toe on the helicopter that flew me there, I was tested for alcohol, barbiturates, amphetamines, cocaine, opiates and cannabis, and was examined by a nurse.
I'd also spent a day doing Helicopter Underwater Escape Training, which involved learning how to remove oneself from an upside-down underwater helicopter, while wearing a helmet, heavy survival suit, lifejacket, external breathing device and, unfortunately for me, no spectacles.
Having managed to pass all of the above I made it to Maui A by 10 the next morning, more than four hours after Mr Lester's first daily meeting, at 5.45am, with the entire crew. (Permanent Maui A staff work 12 hours on, 12 hours off, two weeks on, two weeks off and the platform operates 24 hours a day, 365 days a year.)
Though I was there to see what the PIC did, it turned out Mr Lester spends much of his time in staff meetings.
But a tour of the orange and yellow steel behemoth gives me an idea of what the other 64 workers that can be on the site at any one time - from cleaners and cooks to engineers and welders - are up to.
A permit-to-work issuer, for example, issues a written safety permit before any job can begin on Maui A.
A control room operator manages production flows (the amount of hydrocarbons being extracted) and has a real-time overview of operations from a computerised control system.
On a corner of the structure, a bubble of thick, brown industrial paper surrounds part of the platform's rusted frame, which is being sandblasted by two overall-clad workers.
Mr Lester says the packaging stops any debris falling into the water. Instead, it is collected and disposed of on shore. The only waste that is supposed to go into the Tasman is black and grey water.
"There's no way I'm going to stuff up Taranaki from this platform," he says, picking up a piece of paper on the walkway.
As we walk around, I spot a grey lump of rubbish floating in the sea.
I soon realise it's a seal.
As we arrive at the lowest level, about 10m above the water, I realise there are about 30 of them bobbing up and down in the waves between the platform's huge, steel, concrete-filled legs. One has parked itself on a girder, 3m above the water.
Mr Lester says there are are always about 30 of them floating about. Until a few years ago staff used to fish off the platform but that was stopped due to health and safety rules. Now the only fish staff get have been frozen and brought over on a supply boat.
"It's annoying when one of the seals comes up with a big john dory."
The 57-year-old has been PIC on Maui A since 2011, after returning to New Zealand when his first grandchild was born, from a similar job where he looked after a staff of about 800 in Southeast Asia.
Born and bred in Taranaki, he began his career as an electrician at Huntly Power Station and first worked on Maui A in 1980.
"It's a New Zealand icon, but there's probably a lot of New Zealanders that don't know we exist."
On cloudless mornings the "Maui sunrise" treats workers to a view of Mt Taranaki and Mt Ruapehu and sometimes the view south extends as far as the Southern Alps.
We enjoy a delicious cooked lunch - staff are famously well fed on Maui A - with a menu of peri-peri chicken or marinated pork strips, steamed asparagus and broccoli, wedges and about four types of salad. There is also plenty of tea and coffee, fresh fruit, and containers full of cookies that were baked on-site.
Then, when fog at New Plymouth Airport, threatens the departure of the next helicopter to the platform, I park myself on a plush, black recliner in a room with a pool table and Sky TV projected on to a wall. The possibility of sleeping over and missing my flight back to Auckland is not too daunting.
But the fog clears, so I miss out on a Maui sunrise, and by 4pm I am heading to shore, without once having to put my Helicopter Underwater Escape Training into action.
