2degrees is taking on 60 temporary staff members this week to deal with customer issues but are warning there could still be delays for the next fortnight.
The drive for temps comes after a large number of customers complained about unexplained charges in their bills, double-billing, and issues with the company's mobile app.
Spokesman for 2degrees, Matt Bollard, said the issues stem from the telco's problematic switch to a new customer management software system.
He said he was not aware of systemic issues that would affect billing, but that 2degrees had carried out four or five billing runs in a quicker period than usual.
"We're experiencing a number of billing related queries, which have been complicated by the need to send several billing runs in a short period of time, which create increased call volumes on an already busy Call centre," he said.