The commission’s latest Consumer Issues report shows it received 5073 fair trading complaints in 2015, up from 4377 in 2014.

A quarter of complaints were about 21 traders. Spark topped the list with 140 complaints followed by Vodafone with 133.

Trade Me sellers ranked third (121 complaints), followed by appliance store Harvey Norman (117). Most complaints about the store resulted from online pricing errors made in its October 2015 sale.

Other traders to receive more than 40 complaints include:

• Air New Zealand (88);
• Foodstuffs (59);
• Wilson Parking (50);
• Progressive Enterprises (48);
• Ticketmaster (44);
• The Costume Shop (44);
• Brand Developers (44); and
• Dick Smith Electronics (43).

Price was the most complained about issue, accounting for 26 percent of complaints.

The report also shows complaints about motor vehicle traders increased 70 percent since 2013. Complaints about contracts also doubled over the same period with insurance, phone, power, pay TV and parking companies identified as significant contributors.

Online purchases generated a third of complaints with most relating to the goods supplied or price.

Domestic appliance retailers were also identified in the report. Data showed an increase in complaints about these retailers failing to deal with faulty goods and referring customers to the manufacturer instead. The practice risks misleading shoppers about their Consumer Guarantees Act rights to a remedy from the retailer when a product isn’t of acceptable quality.

Extended warranties being sold with misleading claims about their benefits also featured in complaints.

Lending practices resulted in 164 complaints under the Credit Contracts and Consumer Finance Act last year. Failure to comply with the Act’s disclosure requirements was the most complained about issue, followed by fees and responsible lending. Finance companies were named in 43 percent of complaints.

The full report is available on the commission’s website.