The purchase includes 17,000 kilometres of internet cables and the Australian Singapore Cable and North West Cable System, assets that let Vocus transfer data traffic overseas much cheaper than if it had to buy capacity off another operator.

Management also provided a trading update after Vocus shares were punished on Tuesday and Wednesday, dropping from an opening price of $7.14 on Monday to close at $6.09 on Wednesday. However, shares were up on Thursday at $6.30, a 3.45 per cent increase.

Chairman of the Australian Competition and Consumer Commission [ACCC], Rod Sims, said "the market expressed very little concern over the proposed acquisition".

"The ACCC found that the services supplied by Vocus and NextGen were largely complementary. Where there was overlap, the ACCC considered the combined competitive constraint from other major wholesale suppliers, namely Telstra, Optus, and TPG, would likely be sufficient to limit any harm to competition," the regulator stated in a press release.

"While this proposed acquisition did not raise concerns, the ACCC will continue to keep a close watch on competition in the telecommunications industry especially given recent consolidation and increased vertical integration.

"The four largest retail service providers (Telstra, Optus, TPG, and Vocus) supply over 90% of broadband services in Australia. Any future potential mergers or acquisitions that increase concentration can expect to receive close examination from the ACCC."

Vocus hopes to complete the deal by October, according to a statement released on Thursday morning.

"We are extremely pleased with the announcement from the ACCC and will move as quickly as possible to close the transaction and integrate the business under the Vocus umbrella. We will be working to ensure that we leverage the benefits of our expanded infrastructure platform and increased scale across our customer base," chief executive Geoff Horth said.

"We look forward to welcoming the NextGen team into Vocus as we move into the next exciting phase of growth in the business."

Vocus' share price appeared to follow TPG earlier this week. TPG shares are down 27 per cent since the start of the week after the company announced earnings guidance that was less ambitious than market expectations.

Vocus' corporate and wholesale business units have exceeded sales targets in the first quarter of the current financial year, and "will be further strengthened with the ability to target new customer segments and markets following the integration of the NextGen assets", the company said.

"As the roll out of the NBN gathers pace, Vocus' Australian Consumer business will also benefit from the fibre network that the NextGen acquisition delivers, providing connectivity to the vast majority of NBN Points of Interconnect."

Vocus' NBN subscriber base has continued to grow strongly since fiscal year end with a 21.7 per cent increase in active consumer subscribers since 30 June. The average gross margin per subscriber in dollar terms has remained constrained, with NBN margins in line with bundled copper broadband margins, the company said.

Shareholders will receive a trading update before or at the annual general meeting on November 29. And Vocus chief financial officer Rick Correll announced his resignation this week, but he will stay on for a few months while a replacement is found.

NextGen was created in 2002 as a joint venture between Leighton Holdings and Macquarie Bank. It also runs 10 data centres under the name Metronode, which are not included in the sale.