The Commerce Commission says it cost Telecom $69.7 million to provide home phone services to customers in uneconomic areas in the last financial year.
The cost is less than the $70.7 million for the service the previous year, due largely to a drop in the corporate tax rate.
Telecom will have to pay 66% of the cost - about $46 million - and will be reimbursed the rest by the other telecommunication companies.
Vodafone will pay 26%, Telstra Clear will pay 6% and the other nine companies operating in the market, including 2Degrees, will together contribute less than 1%.
The commission's draft cost calculation will be finalised following a period of consultation with telecommunication companies.
Meanwhile, the regulator has calculated it cost Sprint International $2.15 million to provide a relay service for the hearing impaired.
Telecom, Vodafone and TelstraClear will have to reimburse the company more than 99% of the costs.