A man who lost four fingers at a Wellington joinery firm could not recall a warning to flick off the machine before reaching in.

The 23-year-old fabricator's left hand slipped into the blades of a thicknesser machine while trying to remove jammed timber in May last year.

His former employer, European Profile Company which trades as Thermalframe, appeared in the Hutt Valley District Court on September 2, 2015.

The company pleaded guilty to failing to take all practicable steps to ensure the man's safety at work and was sentenced under the Health and Safety in Employment Act 1992.

The firm makes joinery for windows and employs about nine staff in Lower Hutt.

On May 14, 2014, the man was working on a thicknesser machine, which can reduce the thickness of wood, when a piece got stuck in the machine.

He tried to push it through from the front, but it got stuck again.

He then went to the outfeed end and tried to pull the piece from the other side with his right hand, bracing himself with his left hand on the machine.

His left hand slipped and four fingers were amputated.

Representing WorkSafe NZ, prosecution lawyer Sarah Backhouse said the man did not recall being adequately taught how to unjam the machine.

The man, from Upper Hutt, had suffered a "huge loss" since the incident and worried about how he would help his partner of six years build their long-term future.

He experienced pain in his hand in hot or cold conditions or from vibrations.

He had played guitar for 15 years and the loss of this ability had cost him socially.

The company's defence lawyer, Steve Wragg, said that about a week before the incident his boss noticed him trying to unjam the machine while it was still running and explained the danger.

He also said the man received initial supervised training on the thicknesser.

The parties had since met for a restorative justice meeting where the company paid $15,000 compensation and $2500 toward future training.

It also offered him to come back to work, though the man has since found full-time employment elsewhere.

He had "good feeling" toward the company and did not want to see it face further penalties.

Hutt Valley District Court judge Peter Butler said the 22-year-old machine did not have enough protection and there was a lack of documented evidence of training.

The judge took into account the longstanding company's excellent previous safety record, prompt reparation payment and implementation of new safety steps.

Speaking outside of court, company director Barry Burt said he was satisfied with the outcome.

"I thought the judge had done his homework, which is all one can ask."

WorkSafe chief inspector Keith Stewart said there were a number of practicable steps the company could have taken to keep their worker safe.

"The thicknesser should have had fitted guards to reduce the risk of the operator being injured by the cutters and saw blade.

"There was also no evidence of staff having been trained and no evidence that they understood the way in which the machine should be operated safely, or what they should do if there are events like blockages, for instance.

"We've recently had a lot of workplace prosecutions in the manufacturing sector following on from life changing injuries to people, many of which have involved unguarded machinery."