More than 4500 kilometres of optic fibre will connect more than 2400 educational facilities across the state as part of the four-year contract.

In a statement, NSW minister for education and training, Verity Firth, claimed Telstra said the network would be "the largest in Australia and one of the biggest in the Southern Hemisphere".

"A flexible system means bandwidth provided to schools can be increased or decreased to meet temporary spikes in demand as well as growth or declines in the student population," Firth said.

"This massive program builds on the NSW Government's $158 million Connected Classrooms program and supports the Commonwealth Government's $2.1 billion Digital Education Revolution."

The news comes a day after Telstra said it will in a move to increase speed and bandwidth for multiple users within households.