Telecom is still searching for the reason why some voice services and up to 20% of text messages sent on its XT network in the South failed on Monday night.
The chief executive of Telecom subsidiary Gen-i, Chris Quin, said in the meantime the telco had installed "traffic management" controls which may slow the sending of messages, but should ensure the network operated adequately.
Mr Quin said while the text sending problem was an issue for individual customers, it did not appear to be growing, and monitoring of the network's performance every 15 minutes had indicated it was operating as expected.
A Telecom spokeswoman said compensation was unlikely to be paid because the fault was for such a short period, intermittent and affected a limited part of the network.
Mr Quin said text messaging volumes on Monday night were abnormally high which a small number of cell sites struggled to cope with.
"Monday's problems, I can't say why they occurred.
"The two other outages [in December and January] were unconnected and it is absolutely unfortunate circumstances that both occurred at the same radio network controller (RNC)."
Several people contacted the Otago Daily Times on Tuesday evening and yesterday morning complaining they could not send text messages.
One caller, who declined to give her name, said she contacted Telecom and reset her handset as directed, but said she should not have to do so every morning just to get it to function.
She wondered why it was taking so long to fix and whether Telecom was putting the same resources into correcting the fault that it would if it had occurred in a larger centre such as Auckland.
The biggest concern for callers was that the fault once again affected southern customers and appeared to be in addition to the one which caused a major outage last month for customers south of Taupo.
Mr Quin said the December outage was due to an operational issue which resulted in faulty software, while the January fault was due to a hardware failure.
Both problems had been isolated or removed.
Mr Quin said the texting fault could delay or stop the sending of some text messages, or result in multiple versions of messages being sent because of delays in the reply from the receiving handset that the message had been received.
Mr Quin said Telecom had started work on two new RNCs, in Christchurch and Auckland, which would double its capacity and provide backup.
Two more were planned.
It also planned to extend its XT network to areas served by the older CDMA system and where there was no or limited XT coverage.
Asked about students converging on Dunedin, Mr Quin said Telecom managed potential spikes in use all the time and he was confident the XT system would handle the student influx.
