The Southern Cross Cable Network is supporting the move to high speed broadband in Australia and New Zealand with the completion of the first stage of a big capacity upgrade.

Southern Cross yesterday lit up another 260 Gbits of capacity or 130Gbps on each of its two submarine fibre-optic cables that directly connect both Australia and New Zealand to the US Internet.

The network's sales director, Ross Pfeffer said when completed later this year the current upgrade will take total installed capacity to 860Gbps.

Pfeffer said the current upgrade allows each fibre pair to provide ten times more capacity, lowers capacity cost, enhances the networks resilience and increases the range of services that can be provided.

He said since the upgrade began last September there has been no disruption to Internet services.

"The current upgrade and our new pricing are designed to support the big move to high speed broadband in both Australia and New Zealand," Pfeffer said.

"High Speed broadband requires both capacity cost to reduce and capacity supply to each subscriber to increase considerably.

"Our upgrades make this possible and the impact is already evident with existing and new customers recently making substantial capacity purchases from Southern Cross to support the high speed broadband services they provide."

Back in 2000, Pfefffer saaid the new Southern Cross Cable Network enabled Australasian Internet use to reach the highest levels in the world.

"Now in 2008 we see a much bigger shift in Internet demand resulting from the move to high speed broadband," he added.

By expanding supply, he said it will lower prices.

"The current upgrade allows the Southern Cross cable to keep ahead of demand for just a short time and we are already planning additional upgrades during the remaining 16 years of the network's engineering design life that will continue to take advantage of ongoing technological improvements in transmission technology," Pfeffer said.

"Upgrades are much less expensive than building new cables, they involve the seamless replacement of transmission equipment located in each of our 10 cable stations, they are implemented quickly and they greatly increase the amount of capacity our cable infrastructure can provide".

The Southern Cross Cable Network comprises two submarine communications cables which were first commissioned in November 2000 and January 2001 at a cost of US$1.3 billion.

They provide Australasian broadband users with international connections to the US West coast where global Internet hubs are located.

The Southern Cross Network has been engineered until 2025.

In 2001 total installed capacity was 80 Gbps, in January 2003 the total network was expanded to 480 Gbps and by end-2008 total installed capacity will be 860 Gbps.

With new technology continually improving potential transmission speeds, the ultimate size of the Southern Cross Cable Network is set to exceed the current limit of 2.4 Tbps.

It is jointly owned by Telecom NZ (50 per cent), Singtel-Optus (40 per cent) and Verizon Business (10 per cent).

Southern Cross shareholders made the original US$1.3 billion capital investment back in the late 1990's.