Hydro One had no choice but to pay former CEO Tom Parkinson $3 million in severance, the utility's chair told a legislative committee Tuesday.

"The facts of the matter are that the board agreed it would be in the best interest of the company to have him depart," Hydro One Chair Rita Burak said.

The embattled Parkinson stepped down after Ontario Auditor General Jim McCarter released a report last December questioning some personal expenses Parkinson allegedly charged to his secretary's corporate credit card.

Burak told the legislative committee that the utility board and Parkinson agreed he had to leave the utility after the auditor general's report on his expenses came out.

She says severance had to be paid because there were no legal grounds to fire Parkinson, and severance meant he would leave immediately.

The McGuinty Liberals faced scathing criticism from opposition parties over Parkinson's severance package and $1.5 million annual salary.

A review of executive salaries at Hydro One, Ontario Power Generation and other provincial energy agencies has been since announced.

The auditor general's report says the former CEO billed $45,000 in personal expenses to his secretary's corporate card, and then approved it himself.

With files from the Canadian Press