Labor has requested NBN Co provide the details of a meeting where it was decided $77 million would be paid in bonuses.
NBN Co chief executive officer Stephen Rue says he was appropriately asked to leave the meeting when the decision was made by the company's remuneration committee.
The $77 million figure was revealed in February but it was recently discovered that was divvied up among more than 3800 staff depending on their salary.
"Did the people on the remuneration committee ... consider the fact Australia was in a pandemic when they were considering paying out $77 million," Labor's Kimberley Kitching asked during a Senate estimates hearing.
"I hate to say this, I'm sorry but that's actually a question for the chairman," Mr Rue said.
Senator Kitching has asked for the minutes of the meeting, which Mr Rue agreed to provide on notice.
He said NBN Co hired people with specialist skills in cyber security, data and engineering.
"NBN sources the vast majority of its talent from the corporate sector plus we have some very very important skills," Mr Rue said.
"So we need to have a remuneration structure that reflects the ability to attract and retain staff.
"And we do not pay, I can tell you, we do not pay at the top of the market. We pay very much in the median of the market."
Mr Rue was paid more than $3 million last year.
He referred senators to a letter in last year's annual report written by remuneration committee chair Ziggy Switkowski, where he outlined his consideration of the health crisis.
"Taken in totality and noting the decision to provide additional bandwidth at no charge (hence no profiteering from COVID-19 related growth in demand), the impact upon our commercial outcomes is judged as not material - neither net favourable nor otherwise," Dr Switkowski wrote.
"In the nine months to March 2020, before COVID-19, the performance of NBN Co was trending strongly positive and this continued to year end without measurable deviation. No revision has been made to any budget or target.
"The board has concluded that no variation is called for in our annual remuneration approach."
The issue also arose on Thursday in another Senate estimates hearing.
Finance Minister Simon Birmingham refused to say funding used by NBN Co was in fact taxpayer money.