"Screen acting work on major series is the only form of stable income for professional actors and the end of Spartacus will be a major blow to New Zealand's professional actors who have been cast in increasing numbers in core-cast roles.''
New Zealand film crews, extras, stunt people and equipment hire companies would also be affected.
Ms Majavu said appearing on Spartacus, which airs in 150 countries in more than 15 languages, was a great opportunity for Kiwi actors.
"It can catapult them into a big acting career overseas and definitely work in their favour if they want to go work in Australia or LA because it's an international series.''
New Zealand actor Gareth Williams, who plays the villainous Vettius, said the opportunity to work on a large-scale production like Spartacus was a "helpful stepping stone''.
"It does create opportunities because you can say that you've been in an American TV series, which is usually something you have to go to the States to actually do. It's definitely a big plus that you can do it in your backyard.''
Auckland Actors owner and agent Graham Dunster, who represents Lucy Lawless and other actors in the show, said the producers had been "very happy'' with the results they got in New Zealand and was confident other projects would be brought here soon.
Filming for the final series of Spartacus wraps at the end of the year.
DeKnight promised a "stunningly epic'' final season, which will be called Spartacus: War of the Damned.
The series stars Liam McIntyre as the Thracian-slave-turned-revolutionary out to topple the Roman Empire.
McIntyre took over the role from Andy Whitfield, who starred in the first season then withdrew due to illness. He died of cancer in September, 2011.