2degrees sweetened its mobile data plans for a second time in a fortnight after Spark responded to its earlier move. On Monday, 2degrees announced a plan with 25GB of mobile data for $70. The company points out there are no hot spot or speed restrictions on this plan. Customers can also carry over unused data from one month to the next.

That’s a direct response to the $80 ‘unlimited’ plan Spark announced the previous week. Spark customers get unlimited talk and texts along with unlimited mobile data. However, only the first 22GB of data is delivered at full speed, once a customer goes over that limit, the speed is reduced.

Spark’s move was in itself a response to 2degrees. A week earlier it introduced a 10GB data plan for $55 a month and 15GB for $70. 2degrees was the first carrier to offer an 'unlimited' mobile plan in April of this year when it launched one at $130 a month.

At the time of writing Vodafone hasn’t moved on its plans. It’s best offer is 15GB for $100.

2degrees likes to position itself as the mobile market challenger. It acknowledges that these big data plans are an important statement of intent. After all, they target a specialist user niche.  In a media statement accompanying the announcement chief marketing officer Ray Ong notes the average customer uses less than 5GB of mobile data in a month with few getting close to 25GB.