The 45 staff employed at the studio complex were summoned to a meeting at 3.30pm to be told of the sale.
The studios and business has been bought by a company headed by Wellington businessmen John Feast. The shareholders are Denis Kirkcaldie and studio managers Paul Mainwaring and Gary Watson.
The sale to Avalon Holdings, which Feast chairs, followed a lengthy international search for a new owner. It is unclear how many staff will be re-employed by the new owners and no comment was immediately available from TVNZ.
The deal, which had been under negotiation for months, went unconditional today with settlement and handover to the new owners in March 31 next year.
Feast was not prepared to disclose the price paid but was confident the studios would be able to secure work.
They had been in talks with potential users and were now in a position to offer contracts to lease studios and provide technical support.
The studios - which used to be the production base for TVNZ news, current affairs, drama and entertainment shows, is now largely unused - lost its last TVNZ show when Good Morning moved to Auckland last year.
Since then the racing channels and Lotto have been the main studio users, although Lotto is also being transferred to Auckland next year.
The studios have since picked up a contract from Top Shelf Productions which will produce its new Choice TV daily Brunch at Avalon from next week.
The Racing Board, which broadcasts its Trackside and TAB channels from two production suites, were committed to stay there for the time being, said Feast.
He hoped to keep them there and then draw in more work to keep the studios busy.
He wanted to keep many of the staff on but that depended on the amount of work that could be secured in a highly competitive film and television market.
''The studios have a lot of highly skilled people and we don't want them to leave the region.
Mainwaring, who will be Avalon Studios chief executive, said they had been in discussions with Film NZ, Gibson Group and other production companies so they could build on the ''bread and butter'' work they did for the Racing Board.
The studios and adjoining Avalon Tower, which was TVNZ's head office, opened in 1975, just three years after the switch to colour television.
TVNZ used to employ over 700 staff at Avalon but numbers have dwindled since the 1980s as production and administration moved to Auckland. Its only remaining property at Avalon is the TVNZ Archive.
Hutt Valley Chamber of Commerce president Helen Down said she welcomed the decision to retain the Avalon Studios as a going concern.
"Avalon is an iconic studio with an international reputation and the decision supports the Chamber's strategy of attracting and retaining businesses within the region.''