Colliers International broker Danny Blair, who is marketing the property, said, "It is offered for sale with vacant possession, allowing a new owner to immediately add value through repositioning or redeveloping.
"There is particularly good conversion potential, given the lack of residential and short-stay accommodation in central Hastings.
"Preliminary architectural plans, commissioned by the vendor, envision a 22-unit apartment conversion on the first floor.
"A new owner could develop these plans to create a boutique accommodation offering with undeniable heritage appeal.
"Alternatively, there is scope to reposition the property as a character office space."
The property is a short distance to the town centre and only a one-minute walk to Bay Plaza, the largest food court in the Hawke's Bay.
Blair said the property has played a crucial role in Hastings' municipal history.
"The first post office on the site was built in 1910, after the previous building on Station St became too small.
"It was designed by government architect John Campbell, who included a clock tower in the Edwardian Baroque style."
The 1914 Hawke's Bay earthquake rattled the building so badly that the clock chimed more than 100 times, prompting fears the tower might collapse in another quake.
Alterations to address public safety concerns were followed by further work in 1928.
Three years later the building was badly damaged in the 1931 earthquake. It was rebuilt without a clock tower in 1932.
The restored clock was later installed in a new tower, built as a memorial to the quake, next to the Hastings Railway Station.
The post office operated until the late 1990s, after which it was bought by the Wallace Development Company and refurbished as a medical centre.
The alterations, designed by Chibnall Swann Team Architecture, preserved the building's character facade and parts of the interior, with the bank vault being repurposed as an x-ray room.
The refurbishment won the New Zealand Institute of Architects' Gisborne/Hawke's Bay local award.
Blair said the building's use as a medical facility means its presentation is superior to many other buildings of such character.
NZ Post in Central Hawke's Bay is also on the move.
They partnered up with Paper Plus Waipukurau from September 4, to help them deliver the postal services and bill payments currently available from the Waipukurau PostShop.
New Zealand Post head of retail Mark Yagmich said they were "really looking" forward to again be partnering with Paper Plus.
"We hope people enjoy the fact our new partner is located in a more bustling area of town."
The new agency will be at Paper Plus, 77 Ruataniwha St, just 100m up the road from the current location.
There will be no change to the PO Box lobby.