Christmas is always the hardest time of year for Australia Post - last year was its busiest ever thanks to the boom in online shopping.

As a result, staff are grateful for the modest bonus they usually receive when the government-owned business turns a profit. Last year, they got A$500 ($628) after Australia Post turned a A$241 million profit.

It was, chief executive Ahmed Fahour said, "a gesture of goodwill in recognition of employee performance".

This year, with a thumping profit of A$281m, staff expected something similar.

Instead the Communications Workers Union has branded Mr Fahour a Christmas Grinch, after he decreed the staff bonus would be a A$100 voucher - to be spent at Australia Post stores.

Adding insult to injury, full-time staff will also get in the mail 100 60¢ stamps (part-timers will miss out). The vouchers and stamps will, Mr Fahour said in a briefing to staff, begin arriving in the mail this week.

The Communications Workers Union said this year's Christmas bonus was a stark contrast to Fahour's own salary. He received A$2.77m last financial year, of which A$874,000 was a cash incentive payment. This incentive payment is, the union argues, a rather large bonus.

Asked about this year's bonus payment to staff, Australia Post's general manager of external affairs, Jane McMillan, said that while Australia Post had delivered strong results, "the outlook for the business remains challenging".

"Continued mail volume decline and the need to invest A$2 billion in our parcels and retail network means we will continue to keep our costs constrained," she said.

Joan Doyle, a state secretary of the Communication Workers Union's postal branch, said Fahour's bonus had increased by a third last financial year. Meanwhile, the Christmas bonus decided on for all of his staff would fall, in some cases by 80 per cent this year, Doyle said.

"Mr Fahour doesn't mind calling on our members to work harder and longer every year but when it comes to rewarding them he turns into the Christmas Grinch," Doyle said.

She said it was a "slap in the face" to Australia Post staff who were working their hardest in the lead-up to Christmas to not have this year's profit result recognised as it had been in previous years.

- (Live Matches)