It is 3.2 metres long, about 20kg and can generate 500 pounds of upwards thrust per second - and for a brief period tomorrow it will shut down the airspace above Taupiri.

Craig Packard's homemade, high-powered rocket - dubbed Big Red - will take to the skies along with at least 30 other DIY missiles when rocket hobbyists from around the country gather for National Rocket Day this weekend.

And while the event may be a cause to pause for anyone planning a hot air balloon ride over the Waikato, Mr Packard, 34, assured the Times appropriate precautions were in place.

"We've got a good relationship with the Civil Aviation Authority," Mr Packard said. "They will shut down all air traffic in the area for that flight. Or put a block on for literally minutes."

This is the third launch of the fibreglass rocket by the Hamilton man, who built his first one when he was 17.

"The big appeal for this one was to make a hell of a lot of noise - it's an earth shaker."

Mr Packard, who works as a diagnostics technician by day, said the enduring appeal of backyard rocket engineering for him was all in the construction.

"For me it is building something from scratch. It is about designing and building something from nothing and seeing it fly. And then getting it back into your hands."

The annual event, which is organised by the New Zealand Rocketry Association (NZRA), brings together the organisation's 150 members and offers the public a chance to build and launch their own rockets on site.

The event takes place at Large Farm, Kneebone Rd, Orini. Launch time is 11am.

- © Fairfax NZ News