New Zealand's Commerce Commission proposed targeted improvements to the rules governing fiber networks as part of the regulator's first review of the Fibre Input Methodologies, which set the key regulatory rules for fiber providers under the Telecommunications Act, according to a Tuesday statement.

Shares of Chorus (ASX:CNU, NZE:CNU) rose nearly 1% in recent trading on the New Zealand bourse, while those of Spark New Zealand (ASX:SPK, NZE:SPK) fell nearly 1%.

The proposed improvements include the introduction of a clearer investment test for large fiber network expansion projects, as well as changes to improve the capital expenditure proposal process, including clearer information requirements and adjustments to regulatory timelines.

Large expansion projects would be assessed using a cost-benefit framework under the proposal, including analysis of the value consumers place on fiber services through measures such as willingness to pay.

Fiber-specific cost of capital parameters and other matters will be considered in the second stage of the review. The watchdog is consulting separately on the cost of capital input methodologies that apply across fiber and other regulated infrastructure sectors.