The ABC has already spent more than $2.5 million on external costs defending legal action from journalist and broadcaster Antoinette Lattouf, managing director Hugh Marks has told Senate estimates.

A Federal Court judge last month ordered the ABC to pay $150,000 to Lattouf, finding it breached the Fair Work Act by terminating her employment after she shared a Human Rights Watch post about the war in Gaza.

She had already been awarded another $70,000 in compensation for non-economic loss.

Under questioning from Liberal senator Dean Smith, Mr Marks told Senate estimates that the external costs spent by the ABC could keep rising.

"My estimate was, at the time of the trial, that it was going to be many millions of dollars," he said.

"There are still some final accounts to come in, I und

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