A lack of eager and willing aspirants to take over the Telstra Corp. Ltd. CEO"s chair of ousted boss Ziggy Switkowski may see the appointment of a successor delayed, with Telstra chairman Donald McGauchie conceding a July deadline may not be fixed.

Quizzed by reporters over Telstra"s search for a new leader to take it into fully privatized hands, McGauchie insisted things were on track - but also built-in an escape clause for when a formal appointment will be made.

"The plan is to have a new chief executive in by the end of July," he said.

"Of course you can never be absolutely certain about anything, but at the moment it is going well."

As for how far down the selection track Telstra"s headhunters were, McGauchie chose the measure of time rather than shortlisted candidates to indicate progress.

"Obviously we are [closer], three weeks closer than we were before," he said.

Asked if Switkowski was prepared to stay on after the July deadline, McGauchie said he and Switkowski "haven"t discussed that".

Meanwhile, debate over the cost of upgrading of Telstra"s core network from copper to optical fibre continues to dog the telco, with McGauchie refusing to be pinned down over some estimates that the rollout could cost A$7 billion (US$5.4 billion).

"I have not seen that proposal, I have no comment on it... I don"t know how many times I have to say that."

Pouring cold water on a mooted T3 share buy-back, Telstra"s chairman cautioned that the company could require significant capital to reinvest in upgrading its network.

"We certainly will be watching very carefully the structure balance sheet, because this company has a significant investment going that it needs to make in new technologies for the future - and we have to have the capacity to do that, and get a return on that," McGauchie said.

He also ruled out any public tender process to select advisors for the T3 float in the same way a government had commissioned a scoping study on the sale.

"We don"t have to go through what government has to go through. We have a panel of people that we use and we will want to move very quickly. We certainly won"t want to go through a three-month tender process - that"s for sure".