NBN Co says it is “working flat out” to resolve support tickets for new connections.

The network builder has admitted its expansion of customer service is not on pace with the rollout.

A major source of frustration is a backlog of support tickets lodged by retail service providers (RSPs) or construction partners encountering problems in the field.

NBN Co says it is focusing on “aged tickets” – those that have been open at least four weeks with no resolution in sight.

“Aged tickets happen when something out of the ordinary occurs that means we cannot connect the premises to the NBN access network,” chief network engineering officer Peter Ryan said in a blog post.

“It can be something as crazy as an unclaimed car being left for months right on the exact spot where we need to conduct some civil works”, Mr Ryan said.

The company did not provide other examples of problems being encountered.

Mr Ryan said once the queue was cleared, NBN Co would try not to let the list of delayed cases grow as far again.

“We’re turning our attention to making sure that these aged tickets don’t appear in the first place by working with our delivery partners and internet providers to ensure we’re all properly aligned in the activations process and know exactly what is going on with each premises,” he said.

NBN Co maintains that “the vast majority” of connections are made “without issue”.