Telstra says it is aware of a widespread issue on its network affecting access to a number of websites including Facebook and Instagram.

Users began reporting the issue on the Whirlpool broadband forum, on Twitter and on the telco's Facebook page on Thursday.

Telstra Credit:James Davies

They complained of websites which use the content distribution network Akamai loading slowly or timing out or not loading at all. Both Facebook and Instagram use the Akamai network.

Hundreds of users have reported the problem so far, with users in Sydney, Melbourne, Brisbane, Adelaide, Port Macquarie, the Sunshine Coast and Gold Coast all saying they were affected by it.