The commission decided against changing the processes for Chorus to introduce new variant services with the changes expected to " provide the necessary clarity on the regulated UBA service performance".
The regulator also decided against amending terms for VDSL technology, which it viewed as already being captured by the existing rules.
The final decision comes as relations between Chorus and its biggest customer, Spark New Zealand, remain tense with a TruNet report funded by the network operator today claiming fixed wireless speeds match ADSL copper technology but are significantly slower than VDSL and fibre services.
Spark has been looking to cut its reliance on Chorus's network and has been pitching its wireless service as a viable alternative to copper-based lines, which it has accused of being unreliable in harsh weather. Of Spark's 675,000 broadband connections, 138,000 are on fibre and more than 40,000 are on wireless broadband.
The government is considering whether to deregulate parts of the copper network where it competes with fibre from 2020 as a broader review of the telecommunications regulatory framework. Such a move would include a requirement for Chorus to keep supplying copper services capped at 2019 levels outside those areas.
Telecommunications Commission Stephen Gale said UBA broadband services will be "a key input for retail broadband for some time yet", especially in areas outside the government-sponsored ultra-fast broadband network.
"We are confident that the new standard will not lead to inefficient investment, even if copper is deregulated in UFB areas as currently proposed by MBIE (Ministry of Business, Innovation and Employment)," he said.
The regulator said it would also exempt about 19,000 lines on Chorus' remote legacy network while it waits on the outcome of the government's second phase of the rural broadband initiative.
Chorus shares fell 1 percent to $4, while Spark stock slipped 0.6 percent to $3.63.