Fair Work Commission general manager Bernadette O'Neill told a parliamentary inquiry on Thursday the number of dismissal claims had jumped by more than 70 per cent.

An internal review linked the rise in claims to increasing unemployment and retrenchment rates as a result of the COVID-19 pandemic, Ms O'Neill said.

"What I would say is the increase in unfair dismissals has been unprecedented, significantly higher than from any other period that we from our records," Ms O'Neill said.

The Fair Work Commission was created in July 2009 so did not have records for the Global Financial Crisis.

However, Ms O'Neill believed analysis of the state tribunals of that time would show this rise in claims was higher.

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The Fair Work Commission had come under significant pressure since the crisis, as it had jurisdiction over disputes about the $130 billion JobKeeper scheme.

About 323 disputes had been lodged since the wage subsidy scheme began.

Ms O'Neill said the commission had received extra staff from the Government Solicitor, Federal Court and Attorney General's department to help with demand in the short term.

The commission had applied to the department for further resources going forward.