To add insult, the NBN's own roll-out map says the premises on either side of the PRDnationwide real estate office at 1/66 Princes Highway can connect to it.

Earlier this month NBN Co announced 23,000 premises in Dapto could now connect to the network.

The NBN Co website's roll-out map was updated to show the area - highlighted in purple - has "service available". And the PRDnationwide office is in that purple area.

PRDnationwide managing director Simon Kersten saw the article in the Mercury announcing NBN was available in Dapto.

"We knew it was coming, we knew the Dapto CBD was always going to be one of the first," Mr Kersten said.

"So we've been waiting for it and when we saw the article we thought 'Oh good'."

He then went online and checked with several service providers - Telstra, Optus and AAPT - but they all told him the network wasn't available for his premises.

Even the company's own IT provider came back with the same response.

Entering the PRDnationwide address in the NBN Co roll-out map shows that connection is not available. But enter the addresses either side of the premises and you discover they both have access. Mr Kersten said being able to go online with the NBN would make a big difference to the Dapto office.

"We have terrible ADSL connections out there at Dapto," he said. "Since we moved in there 18 months ago we've had constant drop outs with our broadband and the speed is quite unreliable.

"We've got 12 people working out there and they struggle on an ADSL connection to get any type of speed that's good enough."

An NBN spokesman apologised for the delay and confirmed work was yet to take place to connect the Dapto office.

"The owner will be notified directly in the coming weeks once they're able to order a service from their preferred internet and telephone provider," the spokesman said.