Shiff, who has held senior roles in Telstra Wholesale over the last four years, held the top position at a time when many Internet Service Provider (ISP) customers sharply criticised the telecommunications heavyweight over what they claimed was unfairly priced access to Telstra's network.
Most contentious in recent times was Telstra's pricing of wholesale access above the minimum retail cost for the carrier's own BigPond broadband Internet services. Under intense pressure, Shiff lowered the minimum charges for her wholesale customers back below the lowest retail price.
Shiff continues to report to chief executive officer Sol Trujillo, who said she had led wholesale "through a challenging period".
While Shiff's department has long borne the brunt of frustration from Telstra ISP customers, one reseller was not celebrating the move.
"Deena is a smart operator," said Internode managing director Simon Hackett. "Her departure from Wholesale will be missed".
Hackett said the move indicated a Telstra's continued shift from "the 2004-2005 notion of Wholesale as a business partnership avenue for Telstra", to "a far more agressive retail focus for the organisation". This was to the detriment of Wholesale, he said.
"She is moving to a key portfolio for Telstra -- SME -- and that undercores this shift.
"I do fear for what will become of Telstra Wholesale as the meat in a very public sandwich in the Trujillo framework."
Shiff's new business unit, small to medium enterprises, will comprise staff drawn from Telstra's business and government unit, as well as consumer and marketing.
Her replacement in Wholesale would be announced "in the near future", according to the Telstra.
Shiff will assume the role of group managing director, small to medium enterprises, on 30 January.