* Japan Post to book 40 bln yen annual loss
* Will record 400 bln yen goodwill writedown on Toll Holdings
* Toll Holdings remains "core unit" in group -president
* To cut over 1,700 jobs at Toll in fiscal 2017 (Writes through, updates sourcing, adds president's comments)
By Thomas Wilson and Taro Fuse
TOKYO, April 25 (Reuters) - Japan Post Holdings Co said on Tuesday it will book its first annual loss in at least a decade, after unveiling a $3.6 billion writedown on its Australian logistics arm Toll Holdings Ltd.
Japan Post estimated its loss at 40 billion yen ($362.35 million) for the year ended in March, becoming the latest Japanese company to stumble after a high-profile overseas acquisition.
Japan Inc has spent heavily on overseas mergers and acquisitions in recent years, often paying hefty premiums to tap growth overseas amid dismal prospects at home.
But many bets have failed. Toshiba Corp is expected to report a net loss of around 1 trillion yen due to charges related to the bankruptcy of its Westinghouse nuclear unit, which it acquired in 2006.
The Japanese firm will also in the year to March 2018 cut more than 1,700 jobs at Toll, but will still remain a "core unit" for Japan Post Group, said Japan Post President Masatsugu Nagato at a press conference.
"The price we paid for Toll was high," Nagato said. "The writedown is intended to wipe the slate clean."
Japan Post, a conglomerate that spans postal delivery, banking and insurance, had originally forecast 320 billion yen in net profit for the financial year ended in March, down 25 percent from the previous year.
The company, 80 percent owned by the government, bought Toll in May 2015 for A$6.5 billion ($4.9 billion) in a deal designed to boost its global logistics reach and offset a decline in its domestic postal operations.
At the time of the Toll deal, Toru Takahashi, then-chief executive of Japan Post Co, had said there would be no major job cuts at Toll.
But Toll has been hit with a drop in parcel volumes as Australia's economy is buffeted by falling commodity prices, leading Japan Post to book the impairment loss.
Despite Toll's problems, Nagato said Japan Post was "constantly looking out for other acquisitions, including those beyond the logistics sector."
$1 = 109.9000 yen $1 = 1.3231 Australian dollars Reporting by Thomas Wilson and Taiga Uranaka; Editing by Shri Navaratnam and Randy Fabi