Amazon Studios' Lord of the Rings TV series will be huge but it's a waiting game to get the finer details.

Auckland's been confirmed as the main production base for the series, with pre-production already underway.

NZ Film Commission chief executive Annabelle Sheehan says it's too early to tell what any costs will be.

She told Heather du Plessis-Allan there's still some talks underway, particularly around subsidies.

"It's eligible for the 20 per cent grant, and it's been invited to apply for the five per cent uplift. Discussions are still ongoing with Amazon." 

Economic Development Minister Phil Twyford also can't put an economic figure on it just yet.

He says that will depend on Amazon Prime's budget and plans.

Twyford is refuting suggestions the 20 percent rebate studios receive for spending on productions here is corporate welfare.

"Over the last 20 years this country's built up an industry that generates more than $3 billion a year in revenues and 16,000 jobs. Without the Production Screen Grant, we wouldn't have that."