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Broadband customers across the country were left hanging for five hours after a routine overnight upgrade to Telecom's internet network crashed the system.
Telecom estimate tens of thousands of customers lost access to broadband at about 5.30 this morning until service was restored at 10.35am.
A second 20-minute outage occurred between about 11.20am and 11.40am when Telecom restarted its broadband systems.
Telecom spokesperson Sarah Berry said they were still investigating the source of the fault which affected customers nationwide.
"We suspect it is a fault with a router in Auckland," said Berry.
"We're still watching the network closely today in case of any further issues."
The outage affected customers of both Xtra and seven wholesale ISPs including CallPlus, ihug, Quicksilver, Woosh, MaxNet, ICONZ and World Exchange, as well as some corporate customers.
Telecom recommends people using broadband provided by Xtra or any of the other affected ISPs reboot their modem by switching it on and off when they first use their computers today.
