The Telecommunications Users Association says while it's good Telecom has launched its broadband offering, it's likely its entry-level plan won't provide enough data.
From Thursday the listed company will offer two packages to try to get customers move from the copper network.
The entry-level package gives 50 gigabytes of data at speeds of up to 30 megabytes per second for $95 a month. The next level up offers the same data at more than triple the speed for $125.
TUANZ chief executive Paul Brislen says so far the uptake of fibre has been woeful at less than 3% so it's good to get the big players on board.
And he says the packages are good entry-level prices.
Mr Brislen says Telecom has said it won't be enforcing data limits for the first few months to gauge demand and what sort of usage people will need.
He says that's important because there is a big difference in amount of data between the entry level plan and one of the higher traffic plans.
"If you're on the entry level plan at $95 you get what I would consider to be barely adequate amount of data for my use today, let alone under a fibre world."
Mr Brislen says it's a good way to get people using ultra fast broadband but they are likely to quickly realise that they need more data, because they will use more simply by having a fast connection.
"At the moment Telecom says their average customer uses about 20 gigs of data per month. I would say that if you're assessing how much you'll need, you'll want to look at possibly making that per user."
Mr Brislen says people should be looking at 10 - 20 gigabytes of data for each person in the household.
He says Telecom is being cautious about its rollout because Chorus has experienced problems and is not rolling out in residential areas at this stage.
Mr Brislen says it's taking a long time for Chorus to connect each customer, the failure rate seems to be quite high for those who are connected and the cost associated with the connections has blown out.
Telecom's shares rose 9.5 cents to $2.32 on Wednesday.