The store will undergo "extensive internal refurbishment" and earthquake risk strengthening, according to the proposal.
The Wairarapa Combined District plan lists supermarkets as a discretionary activity in the central business district of Masterton.
Countdown requires a consent, however, because the proposal contains bigger signs than are allowed under the plan -- and because the proposal does not include windows, or an overhead verandah for pedestrians, along the Dixon St frontage.
A Countdown spokesperson said the owners "have had a long-term aspiration to expand and refurbish our Countdown Masterton store and improve customer carparking".
"Subject to resource consent being granted, the proposed expansion and refurbishment will ensure our Countdown Masterton store has the latest fixtures and fittings and is a fantastic offer for our customers."
The proposal contains three "standard new Countdown signs", one each at the Queen St, Dixon St and Worksop Rd entrances.
These signs are 9 metres high and 3.3 metres wide.
The building removals will enable installation of new carparks and a two-way entrance from Dixon St.