More than 22,000 complaints were lodged to The Telecommunications Industry Ombudsman between January and March, marking an increase of 21 per cent compared to the previous quarter.

The Ombudsman's Quarter Three Complaints Report found problems across all service types, including connection issues, affecting residential consumers and small businesses.

Nearly 53 per cent of complaints included fault issues, as well as challenges with service quality and connection.

Concerns about mobile coverage and other phone-related issues were the most prominent, garnering at least 8500 complaints.

There was also a 31 per cent increase in disputes relating to internet services.

The latest figures come after a two-year trend of declining complaint numbers.

"This quarter's increase in complaints is a reminder that telcos need to focus on working with consumers to resolve complaints before they escalate to us," Ombudsman Cynthia Gebert said.

"Consumers need to be able to rely on their phone and internet services.

"When problems happen, the telcos need to work with consumers to identify and repair the problem."

Complaints from residential consumers increased by more than 22 per cent compared to the previous quarter, while complaints from small businesses rose by over 12 per cent.

Australian Associated Press