Telstra was the most complained-about telecommunications provider in the last quarter of 2016, taking over industry rival Optus.
That's according to the Telecommunications Industry Ombudsman (TIO) figures, with data spanning complaints from mobile, landline and internet services from small business customers and residents.
Telstra rallied a total of 6.8 complaints per 10,000 services - an increase from 6.0 compared to the previous quarter.
Optus came in second place with 6.7 complaints. However, the telco saw a continual fall this quarter after topping the complaints list for the majority of 2016, finishing the last quarter on 7.2 complaints.
Vodafone followed Optus in third place, recording 5.0, a drop from 6.2 complaints in the previous quarter.
Both amaysim and Pivotel tied in ranking for fourth place with 1.0. In the previous quarter, amaysim registered 1.1 and Pivotel saw 1.3.
According to the TIO, complaints rose 33.3 per cent compared to the same period in 2015, which was at a record-low with 4.8 per cent complaints per 10,000 services.