The Commerce Commission has released its proposal to retain the power that helped 2 Degrees claim a place in the local market.
The Commission has the power to require the country’s three mobile network operators to provide wholesale access to their networks for a period of time to any new network operator.
The watchdog wants to maintain the power, just in case it is required.
Roaming allows customers of one mobile network to use another network when they are outside their own provider’s coverage area - this regulation would enable a new operator to quickly expand its coverage beyond its own initial physical network.
“National mobile roaming helped 2 Degrees deliver a nationwide service for its customers from day one, in advance of rolling out its own national network infrastructure," Telecommunications commissioner Dr Stephen Gale said today.
"We believe the power to regulate remains an important competition safeguard, especially with 5G networks and potential new entrants on the horizon."
Any new mobile provider will almost certainly require a national roaming arrangement while 5G rolls out, the Commission said.
"We note that Blue Reach Services has entered as a fourth provider and has publicly stated their intentions to roll-out 5G," Dr Gale added.
The Commission also said it felt sufficient competition had not yet emerged in the supply of roaming services, despite 2 Degrees completing its network build.
Under the Telecommunications Act, the Commission is required once every five years to consider the deregulation of certain services, including national mobile roaming.
It is inviting submissions on its preliminary view by 5pm, 30 July. A final decision is expected on 4 September.