A Consumer NZ survey on mobile and broadband services has returned poor results for Vodafone and Spark.

From customer services to value for money, Vodafone finished bottom - 75 per cent reported spending too long on hold and about 50 per cent said the service was poor once they finally reached a representative.

"Vodafone needs to spend less on flashy advertising and more on sorting out its service," Consumer NZ chief executive Sue Chetwin says.

Vodafone wasn't the only large telco player displeasing its customers, however, with main New Zealand rival Spark also clocking below-average overall satisfaction results.

The poor performance of the two biggest telcos dragged down average overall satisfaction scores to 54 per cent for mobile providers and 49 per cent for internet service providers (ISPs).

Smaller providers returned better results, with Spark-owned Skinny returning a satisfaction score of 75 per cent, and 2degrees 61 per cent.

The top-rated ISP was Flip, with an overall satisfaction score of 70 per cent, but it doesn't offer fibre. Among ISPs that do, Skinny customers reported fewer problems than others.

As New Zealanders are doing regularly with power companies, Ms Chetwin urged consumers unhappy with their service for mobile or broadband providers to switch.

Consumer NZ's survey suggests fibre is now the most common type of residential internet connection.

However, for many households, the installation process has been far from plain sailing, with one in three fibre customers encountering issues during installation.