Telstra today advised customers to ignore a hoax SMS promising a AU$200 credit if they forward the message on to 10 people.

Telstra Head of Consumer Marketing, Jenny Young, said that the message was not sent by Telstra and encouraged customers to simply delete the message.

"There is no truth to the message that by forwarding the SMS on, customers will receive a $200 credit from Telstra," Ms Young said. "We want to dispel this myth before it spreads widely.

"Telstra does not condone these annoying chain letter style spam messages but, unfortunately, Telstra cannot prevent these messages from starting."

Telstra does not know who started the SMS hoax or their motivation for doing so.