Environment Canterbury has been carrying out shoreline and wildlife assessments on Monday, including aerial observations.
It has also been making observations on the water with Whale Watch and Dolphin Encounter to ensure wildlife are not being affected by the spill.
So far ECan staff have not observed any impacts on the wildlife populations.
The small commercial fishing boat, Ruff-Enuff, was successfully removed from the water and placed on the roadside using a digger after it ran aground near Goose Bay.
Said ECan regional on-scene commander Richard Purdon: "When the vessel ran aground, tanks were ruptured and about 600-litres of diesel fuel was lost.
"Some localised diesel sheen was visible in the immediate area of the grounding and a large, but thin, plume of diesel was observed moving north towards South Bay.
"Diesel is a very light fuel which spreads and evaporates quickly, which is likely to happen over the coming days."
The skipper and the crew are safe.
About 60-litres of mixed fuels in 20-litre containers was removed from the vessel before it was towed above the high tide mark at 9pm.
- Mr Purdon is urging members of the public to call ECan's incident response line on 0800 765 588 immediately if they see oil on the water or any wildlife showing signs of distress due to oil. You can also report this using the Snap Send Solve app.
