"Uggggh Internet has been unusable the last few days. Yay for unmetered Netflix @iiNet but also thanks for the congestion," one consumer wrote on Twitter. "Might this explain why my iiNet ADSL speeds seem to have slowed in the last week or so?," another told Fairfax Media. "That is, there is a bunch of new streamers online, and they are clogging the system up?" Another wrote: "the start of Netflix has also shown up the poor state of our current internet infrastructure. Almost immediately Netflix came on line, my evening business grade service slowed down so other stuff I was streaming ... began having buffering issues and slowing load up." But iiNet chief executive David Buckingham pointed to what he called "mass service disruptions" on Telstra's copper network as the reason some customers suffered slower connection speeds. "We are having countless mass service disruptions on the Telstra copper network right now, so it might be people caught up in those who are commenting," Mr Buckingham said.

"Any technical issue would quite easily affect Netflix streaming, just like any other video download." But a Telstra spokesman said a mass service disruption (MSD) was not the source of iiNet's complaints. "A 'mass service disruption' refers to a fault on the copper line, not the kind of congestion on a network that it is being reported iiNet is experiencing," the spokesman said. "We can't comment on the performance of the iiNet network. iiNet is responsible for the end-to-end management of their network and iiNet customers need to contact them if they are experiencing problems."

But he said Telstra's fixed network had experienced "higher-than-usual fault rates" during summer. "In line with the multiple extreme weather events across Australia this summer, including cyclones, high rainfall and bushfires in different parts of the country, we have been experiencing higher-than-usual fault rates. However, last month, we still achieved an average service availability of 99.69 per cent for voice services on the copper network and a fault free rate of 98 per cent." The spokesman defended the company's copper network, saying it could service the hundreds of thousands of Australians who have subscribed to video streaming services, such as Netflix, Presto and Stan this year. "Most Telstra customers should be able to stream high definition video, with typical download speeds up to 8Mbps for ADSL and up to 20Mbps for ADSL2+," he said.

"Five years ago hardly any video traffic was carried over Telstra's fixed network. Now it accounts for 30 per cent of our overall fixed network traffic. "Each month there is more than 27.5 petabytes of video traffic carried over our fixed network. That's equivalent to watching more than 13 million hours of high definition videos each month." Ovum analyst David Kennedy said video streaming was unlikely to hinder internet connection speeds. "I'm not actually anticipating a lot of problems because the telcos have seen this coming, years off," Mr Kennedy said. "Basically every exchange has fibre connected to it. They can carry gigantic amounts of traffic.

"All that's required to upgrade that capacity is to upgrade the electronics and in a lot of cases that can actually be done by software." Foxtel, which is half-owned by Telstra, launched a streaming joint venture – Presto Entertainment – with Seven West Media in January. The telecommunications company has an unmetering deal with Presto. Mike Sneesby, chief executive of Stan – a partnership between Nine Entertainment and Fairfax Media, owner of BusinessDay and The Australian Financial Review – said Australians had embraced video streaming. He said Stan, which also launched in January, has more than 100,000 customers and is streaming more than 1 million hours of content a month. Stephen Langsford, the chief executive of Perth-based Quickflix – which streams more than 1.5 million hours of video a month - said the slower connection speeds were probably more an internet service provider (ISP) problem.

"We stream over 1PB of content every month to over 400 ISPs – the majority of this being in the peak one to two hours of each day," Mr Langsford said. Loading "For this volume of business, we have very few complaints about internet speed or performance. "However there are huge differences in performance between ISPs – which tells us that this might be an ISP problem and not a general internet backbone problem."