Precinct developers at Ngai Tahu Property had talked with potential leaseholders since the middle of last year about occupying the $20 million cornerstone of the five-building complex and exclusively revealed all to the Queenstown Times.
Anderson Lloyd and WHK confirmed agreements with Ngai Tahu late last year to occupy the building.
Anderson Lloyd will move temporarily to Ngai Tahu's building four, along with NZ Post, before relocation in October next year.
Contractors began excavations for the new three-storey building last Wednesday.
"POP One" will provide 3125m of new retail and office space and a basement car park with 32 bays.
Ngai Tahu Property development manager Gordon Craig, of Christchurch, said NZ Post would move into half of the ground floor.
Negotiations were continuing with a "multinational financial company" to occupy the other half and he hoped to complete an arrangement in the next few weeks.
The first floor would be taken up entirely by WHK Cook Adam Ward Wilson.
Up to 86% of the second floor was set for Anderson Lloyd and the remaining 14% available to the company in negotiations.
Anderson Lloyd Queenstown general manager Mark Beale said the extra space would enable the firm of 30 lawyers and support staff to hire another 15 personnel over the next decade.
"Ngai Tahu met our needs in terms of quantity for future growth, a central location and a good mix of corporate tenants," he said.
WHK Cook Adam Ward Wilson chief executive Philip Mulvey said the firm was looking forward to merging its two offices in Queenstown under one roof.
"The new premises support our growth aspirations for our Queenstown office and are a positive addition to the central business district," Mr Mulvey said.
"Good working conditions are key in attracting good quality professional staff to the area.
"An all-weather public piazza beside Horne Creek will create a thoroughfare of outdoor seating, plantings and verandas between Camp, Ballarat and Stanley Sts."
Ngai Tahu was considering how to incorporate old greywacke stone salvaged from the demolished post office.
The developer would be seeking tenders for a cafe on the ground floor.
Mr Craig said Ngai Tahu was going for a specific product mix and permitted use.
"We're not looking for another bar, but a cafe that can deal with morning, noon and evening parts.
"We haven't tried to create a glass precinct. It's all sympathetic to the existing buildings."
Naylor Love Construction won the tender for building one and built all the other buildings in the precinct.
"We think they've done a fantastic job on the site and look forward to continuing the relationship."
The "POP Four" building is to go on the site now occupied by the post office building.
The 400sq m ground floor would be available for retail or food tenants.
The first and second floors would be given over to office tenants and Ngai Tahi would be seeking these in the next few months, Mr Craig said.
Ground works for the final precinct building began earlier this year and then stopped in April.
Resource consent conditions sought to avoid disruption to the trout spawning season in Horne Creek, which runs through the precinct.
Mr Craig said the tenants had an interest in sustainability and it was part of the brief to meet their expectations.
The building was designed to incorporate rainwater harvesting, heat recovery air conditioning, automatic daylight control lighting and carbon dioxide monitoring controls.
"On completion, the building is anticipated to be equivalent to a four-star rating," he said.
