Spark has been identified as New Zealand's most complained about company in a report released by the Commerce Commission today.

The Consumer Issues 2015 report notes the telecommunications company received 128 complaints under the Fair Trading Act last year.

This was closely followed by Vodafone, which received 112 complaints in 2014 and Auckland Academy of Learning, which received 106 complaints.

ANZ Bank received the fourth most complaints, with 99, followed by Trade Me sellers, with 78 complaints.

The commission noted that 31 complaints to Spark and 15 to Vodafone were triggered by the companies' introduction of a $1.50 paper invoice processing fee.

The complaints were considered by the commission to not be a breach of the act.

A quarter of New Zealanders' complaints under the Fair Trading Act relate to just 24 traders, the report found.

It also found that online trading generates 55 per cent of Fair Trading Act complaints -- double the number laid against physical retailers.

The data comes from a range of sources including the commission, Government and community agencies.

The commission also found that telecommunication providers and home appliance retailers continue to generate the most complaints overall.

Meanwhile, motor vehicle credit contracts generate 30 per cent of credit complaints, and finance companies are the most complained about lenders -- followed by mobile traders.

NZ's most complained about companies:

• Spark NZ Trading Limited - 128
• Vodafone NZ Limited - 112
• Auckland Academy of Learning Limited - 106
• ANZ National Bank Limited T/A The National Bank and ANZ - 99
• Sellers on Trade Me - 78
• New Zealand Business Funding Centre - 50
• Progressive Enterprises Ltd (Countdown) - 45
• Air New Zealand Limited - 43
• GrabOne Limited - 39
• Noel Leeming Group Limited (Noel Leeming) - 35
• Brand Developers Limited (TV Shop) - 35
• Foodstuffs (NZ) Ltd (New World/PAK'nSAVE/Four Square) - 34
• ASB Bank Limited - 33
• Parking Enforcement Services - 31
• DSE (NZ) Limited (Dick Smith Electronics) - 30
• DB Breweries Limited - 29
• Callplus Services Limited (Slingshot Communications) - 27
• Dead Sea Skincare - 27
• The Warehouse Group Limited (The Warehouse) - 26
• NZ Sale Limited - 26
• KLiB Technologies Group Limited (24/7 Hosting and Web Design) - 25
• Two Degrees Mobile Limited (2degrees) - 24
• PB Technologies Limited - 24
• IPL Laser Solutions Limited - 23