He wandered outside his home about 4.30pm when the rain had stopped and noticed the smell of oil in the air.
The oil had splashed on his lighthouse, across the boundary of his lawn and over the retaining wall separating his property from the high tide mark - about 1.5 metres high.
The oil slick seen at Mr Neill's property in Mangatapu.
Mr Neill said he phoned the coastguard and authorities straight away.
"It's disgusting, there should have been a plan in place to stop it from getting this far. I thought they would have had some kind of spill control."
Mr Neill told the Bay of Plenty Times the oil was still lapping at his property's edge about 5.30pm last night.
"I've never seen anything like this before and this time of year all the migrating birds come in and do their feeding."
Amanda Witherell, who lives with her partner on a boat in the Tauranga Marina, said she noticed the smell of oil in the air about 3.30pm.
"I could smell diesel.
"I was about to run some rubbish up to the tip here but as soon as I got off our boat I could see black diesel all over our dock lines and splashed up the side of our hull. It sort of collected around our boat in the dock.
"There is a lot of debris that comes through the marina, especially in a storm, like with bark, leaves and seaweed.
It's disgusting, there should have been a plan in place to stop it from getting this far.
"There is a raft of that stuff all covered with oil now."
Liza Schneider, founding trustee and veterinarian for ARRC Wildlife Trust, said it was more than likely other birds would be affected by the oil spill.
"Shags hang out in groups."
The biggest risk to the creatures would be if they were to start preening themselves after being covered in oil, she said. The Bay of Plenty Regional Council commander on scene, Adrian Heays, said he had no idea how much oil had been leaked or how far it had reached by last night.
Image 1 of 8: A large slick of oil can be seen at Tauranga Marina. Photo/Amanda Witherell
"It's impossible for us to estimate how much has leaked," he said. "We don't know when the spill began.
"It was only discovered once the oil was on the water."
Mr Heays said at this time the tide was coming in, and it was unknown how far the tide had taken the spill.
Responders managed to track sheens of oil on the water's surface to as far as the Matapihi Railway Bridge but poor weather conditions hampered efforts to trace oil any further, Mr Heays said.
Responders will head out at first light today to establish how far the oil has reached and how serious the spill may have become.
Mr Heays said there was a considerable amount of oil located under the wharf at the Port of Tauranga.
However, he could only comment on what the council had seen so far.
The council was unaware of the Maungatapu spill or affected wildlife until the Bay of Plenty Times reported it to them.
