Three brands of laundry detergent failed to clean clothes any better than water when washing products sold in New Zealand were put to the test.

Consumer NZ has released results after conducting a product review on 46 laundry soaps – including powder, tablets and sheets – to evaluate their efficacy and determine their performance.

The Warehouse, which owns one of the worst-performing brands, says it was treating the results seriously and now looking at the formula in light of the findings.

Scores were given based on the detergent’s ability to treat 10 different common stains such as grass, olive oil, ice cream and everyday grime in a front-load washer and ranking them out of 10.

The tally was then combined to create a final score out of 100, with three categories - poor, average and good.

According to Consumer NZ, at least three products proved no better than washing in water, while a selection of Persil products proved the most effective.

Two detergents, Shotz Laundry Liquid and EcoLiving Laundry Detergent Sheets (with lavender), scored 27 out of 100, putting their efficacy on par with washing the load of laundry with water.

The two detergents cost $10 and $10.50 respectively.

Ryan Murphy, general manager of groceries at The Warehouse, said the company was “surprised by these results”, given Consumer NZ previously gave its Shotz range a better rating.

“We regularly hear positive feedback from our customers about Shotz, and have the range independently tested to ensure quality.

“However, the result for this product aren’t the standard we or our customers expect, and we’re treating them seriously.

“We’re going to review the formulation to ensure it delivers the performance our customers expect and deserve.”

Re.Stor Laundry Detergent Sheets (fresh linen scent), which is priced at $11.99, received a lesser score of 24 out of 100.

The Re.Stor sheets received poor ratings for its ability to remove every type of stain except baby food, which received an average rating.

In comparison, washing with just water received poor ratings for all except baby food and grass and mud stains, which were both given average ratings.

But the poor performance of the laundry sheets wasn’t surprising, Consumer NZ’s head of testing James le Page said.

“They only weigh a couple of grams, so when you put them in your machine, they’re just not going to do a good job compared with a capful of laundry liquid or scoop of powder, both of which have the potential to contain more active ingredients.”

The two sheet detergent products tested - EcoLiving Laundry Detergent Sheets (L) and linen-scented Re-Stor Laundry Detergent Sheets (R) - scored the same or less than water. Photo / Consumer NZ

However, it was possible laundry sheets could improve their scores over time.

“They’re early in their developmental journey as a product. They’re years behind the other options, so they’re playing catch-up,” le Page said.

Re.Stor and EcoLiving have been approached for comment.

Persil, meanwhile, had the three most effective laundry detergents in the Consumer NZ test.

Persil Ultimate Powder was the top-scored product, receiving 94 out of 100.

It was the only product to receive good ratings for all types of stains.

In second and third place was Persil Active Clean Powder, with a score of 92, and Persil 3 in 1 Ultimate Capsules, with a score of 89.

Overall, Consumer NZ gave 10 products a tick of approval, and le Page said people should review their detergent of choice to determine whether it’s worth making a switch.

“You might find something that will do a better job for a better price.”

Best-performing laundry detergent:

1. Persil Ultimate Powder - 94/100
2. Persil Active Clan Powder - 92/100
3. Persil 3 in 1 Ultimate Capsules - 89/100
4. Ariel Original Liquid - 86/100
5. Ariel Allin1 Pods Original Capsules - 79/100
6. Laundromate Laundry Powder (Oceania Coastal Breeze - 79/100
7. Persil 3 in 1 Sensitive Capsules - 79/100
8. Ecostore Ultrapower Citrus Fresh Powder - 77/100
9. Laundromate Laundry Liquid (Cotton Flower & Freesia) - 77/100
10. Persil Active 3 in 1 Capsules - 77/100