Customers south of Taupo had problems making and receiving phone calls, sending text messages and using broadband services after the 11am outage -- the second major crash in as many months.
Telecom had hoped to have services restored by 1pm, but most customers had to wait until 4.30pm to be able to use their phones, with some South Island users still waiting this morning.
Spokesman Mark Watts told The Dominion Post a decision on compensation was yet to be made.
The cause of the outage was not yet known but it appeared a network switch at a Christchurch site was involved, he said.
Telecom chief executive Paul Reynolds has commissioned an independent review into yesterday's crash and the earlier one.
He said the company was already working on improving the capacity and design of the network, which launched in May.
Customers were offered a day's mobile usage, plus a weekend of free calling, after the December 14 network crash.
That fault was attributed to corrupt software, uncovered during maintenance, triggering a network-load equipment failure.
