AusPost chief Christine Holgate has been stood down and the board put on notice.

Ms Holgate has been instructed to step aside during an investigation into the purchase of $12,000 worth of Cartier watches as a reward for four senior managers.

The review will be conducted by the communications and finance departments, as well as an external law firm. It is expected to report back to cabinet for decisions on further action.

Australia Post bought the four Cartier watches in October 2018 to reward four senior managers who had helped secure a deal to allow banking services at post offices, and estimates hearing heard on Thursday.

“There were a small number of senior people who had put an inordinate amount of work in and they did receive an award from the chair [and] myself on behalf of the board,” Ms Holgate said.

“They were Cartier watches of about a value of $3,000 each.”

John Stanhope, who was chair at the time, told reporters he “can’t remember authorising it back in October 2018”.

Ms Holgate said the purchases were organised through her office, but both she and her chief financial officer could not say which corporate credit card the payment was made through.

She was asked whether she thought it appropriate to use taxpayers’ money to buy Cartier watches for already very well-paid Australia Post executives.

Ms Holgate insisted she had “not used taxpayers’ money”.

“We do not receive government funding. We are a commercial organisation … It was a recommendation from our chair that these people get rewarded,” she said.

Australia Post is fully owned by the federal government and classed as a government business enterprise.

Australia’s postal union says the problems at the top of the organisation run “far deeper than watches”.

“This largesse is a symptom of broader problems at Australia Post and how management is out of touch with workers,” says Greg Rayner, the national secretary of the CEPU communications union.

“The pressure for posties and workers has been enormous, with mounting delivery backlogs due to the new reduced service model.”

He says the Federal Government is ignoring broader problems at Australia Post, including increased pressure placed on postal workers.

He called for the entire board to be stood aside while an investigation is undertaken.