Internet and phone companies that use Telecom's network to sell their services experienced delays of up to two weeks over Christmas for customers wanting to sign up for broadband.
Telecom wholesale spokesperson Melanie Marshall said it had a skeleton staff on over Christmas who were unable to attend
to the provision of new broadband connections in time for its wholesale customers, Callplus, TelstraClear, Orcon and ihug.
Marshall said the companies signed on more broadband customers in December than expected, which created unexpected work for Telecom.
Marshall said: "It's good news for wholesale customers because they are getting more customers than they thought."
There was also a backlog of wholesale customers needing new broadband connections in November, which spilled over to December.
"In some cases new connections took two to three days longer because of the statutory holidays," she said.
Woosh marketing manager Nick Clarke said Telecom did not make provisions for broadband customers between December 22 and January 9.
"The problem has been sorted out now but it was a bit touch and go over the Christmas period. Luckily it only affected a small part of our customer base - most are wireless."
Clarke knew of one customer who became tired of waiting for a new broadband connection with Woosh during that period but was able to sign up with Telecom straight away.
At Callplus delays for broadband connections jumped by nearly half a day, to three days over Christmas.
ihug and TelstraClear said disruption to their services was minimal.
Orcon regulatory manager Scot Bartlett said: "Other ISP's should stop finding excuses for moaning. People need holidays and you can't expect everything to be completely smooth for the week over Christmas."
