Tiscali has criticised the BBC following suggestions that internet service providers (ISPs) might be limiting user access to the broadcaster's iPlayer application.

ISPs are concerned about the increased load that such TV-on-demand sites are placing on their networks. Regulator Ofcom has warned that the cost of renewed infrastructure required to support such services could amount to £830m by 2011

Last week Ashley Highfield, head of future media at the BBC, threatened to " name and shame" providers that are restricting iPlayer traffic. But now Simon Gunter, head of strategy at Tiscali, has accused the broadcaster of aggravating a difficult situation.

"The question is about whether we invest in extra capacity or go to the consumer and ask them to pay a BBC tax," said Gunter.

"Inflammatory comments about blacklisting ISPs do not help. There seems to be a lack of understanding about how networks are built. Either we are not explaining it properly or it is falling on deaf ears."

But the increased strain caused by the iPlayer is small enough to be manageable, according to Highfield.

"We estimate that currently the iPlayer is having between 3-5 per cent impact on the network," he said.