Shannon said the tour cancellation left a gap in the calendar for some cities, but the National Youth Orchestra would play in Auckland on August 31.
The NZSO expected The Hobbit recordings to boost its coffers at a time when the Government said it must find new revenue sources.
The production was expected to be lavish.
"It's not the cheapest production in the world," Shannon said of the filmmakers.
"They tend to do things very thoroughly and very well.
"We haven't seen the score yet ... but we would certainly be operating under the assumption that it would be our full orchestra."
This year, the NZSO has also recorded for Escape Plan, starring Hollywood stars Sylvester Stallone and Arnold Schwarzenegger.
Last year, its credits included the Tommy Lee Jones war movie, Emperor, and the Andrew Adamson-directed Mr Pip.
Production company 3 Foot 7 has spent about $447 million on The Hobbit trilogy.