New ABC managing director Michelle Guthrie experienced a baptism of fire in her first appearance before the Senate, facing tense questioning from Labor and Coalition senators on her fourth day in the job.

Ms Guthrie, who officially took over from Mark Scott on Monday, was grilled on reported plans to shut the ABC's fact-checking unit, alleged left-wing bias, staff trips to Cannes and the broadcaster's decision to commission its own typeface.

Ms Guthrie told senators she was booked to return on the last flight from Canberra to Sydney at 7pm, an hour-and-a-half after the ABC's Senate estimates session began. This displeased some senators, who expect public officials to answer all their questions.

Senators usually have three opportunities a year to ask officials from public bodies such as the ABC about how they are spending taxpayer funding.

After initial attempts to keep questioning brief, Ms Guthrie was later told she would not be allowed to leave early to make her flight.

Firebrand Labor senator Sam Dastyari was frustrated at attempts to limit his questioning of Ms Guthrie and other officials over Fairfax Media reports about an ABC board member's handling of a whistleblower who alerted her to a corruption scandal at corporate giant Leighton Holdings.

This occurred when Kirsten Ferguson, appointed to the ABC board last year, was Leighton's ethics committee chair.

Ms Guthrie and other ABC officers declined to say whether the issue was discussed at the broadcaster's most recent board meeting - a decision a furious Senator Dastyari said was "astonishing".

When asked whether the ABC would axe its fact-checking unit, following a minor funding cut in Tuesday's budget, Ms Guthrie said final decisions would be made within 10 days. But she stressed the ABC would be prioritising its "local and regional reporting" when deciding which services it maintained.

ABC officials confirmed politicians had made formal complaints about ABC Fact Check verdicts, but said this would not influence any decision on its future.

Liberal senator James Paterson why the broadcaster had spent money on creating its own "OneABC" typeface rather than use an "off the rack" font.

Ms Guthrie, a former senior executive at Google and News Corp, said it was important for the ABC to have consistent branding across its various platforms.

Senator Paterson also asked Ms Guthrie whether she agreed with former Media Watch host Jonathan Holmes' claims that the ABC's capital city radio presenters tended to have left-wing views.

Ms Guthrie had not read Mr Holmes' article, but said she believed the ABC was committed to impartiality.

Nationals senator Bridget McKenzie demanded to know how Ms Guthrie would tackle staff perceptions the ABC was too "Sydney-centric".

The ABC took a swipe at Senator McKenzie earlier this year for demanding the ABC board include two directors living in regional areas, given she lives in Elwood, in inner-city Melbourne.

ABC chief operating officer David Pendleton told Senator McKenzie the ABC spent nearly $150,000 sending 10 representatives to the Cannes film festival last year.

Mr Pendleton said the majority of people attending were from the broadcaster's commercial arm and were selling ABC content.

Senator McKenzie said she was not surprised many staff had added on personal holidays to their work trips.

"Heading over to Cannes and I might just spend a couple of weeks on the Riviera," she said.

Ms Guthrie repeated her message to staff this week that improving diversity at the ABC so it better represents modern Australia would be one of her top priorities.

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