NBN Co chief Mike Quigley faces groundhog day at Senate Estimates next week after the Coalition all but confirmed they would attempt to derail the hearing with another Alcatel bribery grilling.
Speaking on Perth's 6PR radio, opposition communications spokesman Malcolm Turnbull said he thought Quigley had "quite a bit of explaining to do", despite months of denials of direct involvement in the scandal.
Asked what was likely to happen in the Senate next week, when Quigley fronts a late-night Estimates sitting, Turnbull said: "Well, I think he's going to be invited to give a full and frank explanation [t]here.
"And you know Senator Conroy will say this is a witch hunt, and we're trying to smear him and really nobody is," Turnbull said.
"He [Quigley] really needs to actually put all of the facts on the table."
Turnbull had previously told Quigley at an NBN Co transparency review in Sydney that he was satisfied the NBN Co chief had told the truth.
The re-surfacing of the issue came as NBN Co appeared close to finalising a complex deal with Telstra.
News reports indicated that the multi-billion dollar deal could close sometime next week.
But it did not rate a mention on 6PR, where talk concentrated on a news report that compared NBN Co's low number of "subscribers" with the salary expenses of employees, and Quigley's knowledge of a bribery scandal at Alcatel while he was an executive of the vendor.
The NBN technically has no subscribers, only triallists.
Turnbull said Quigley should have had the "candour and openness" to give the Government a "heads up" on the SEC investigation before he was hired to NBN Co's top job.
NBN Co appears before Senate Estimates from 7pm on Thursday 16 July.