Independent tester finds Telecom's 3G mobile network fastest in most areas. 

UPDATED 3pm: Telecom says problem has been resolved.

Telecom has advised that issues affecting its XT network in parts of the country are resolved.

Customers in the lower North Island and parts of the South Island have reported issues with data connections to the network.

Spokeswoman Katherine Murphy said at 12.30pm some customers had reported issues with data usage and the company was looking into it.

On twitter, Telecom suggested customers having XT data problems should disconnect and then reconnect to the network.