"For me it's more of a theatrical event, it's not a fireworks kind of spectacle," he says.

"I'm trying to tie in some of the thematics that [creative director] Robyn [Archer] has set out, for example the use of the words is important. We also would like to talk about the celebration of the birthday, so we have some birthday elements in the fireworks. I can't say too much yet."

The fireworks will also be organised along the axis of Canberra's original design, to incorporate the spirit of the city into a distinctive display.

It's now almost a year since Ruigrok van der Werven first sat down with Archer and the designer of the entire birthday party, Geoff Cobham, and worked out how to make their vision a reality in the day's crescendo moments.

"Geoff gave me a brief as to the word he wanted to use and a combination of audience engagement and fireworks," he says.

The mystery word, made of eight-metre-high steel letters attached to catamaran-style vessels, is now being set up on the lake out of view.

They will begin moving around the lake at around 8.00pm, when the Centenary Symphony begins, like a "giant game of scrabble", and by 8.45, they will have formed the mystery word as the fireworks go off from 13 separate points around the lake.

He says he has been interested in pyrotechnicians since his days growing up in the Netherlands.

"Like in Canberra, you were allowed to have fireworks at New Years', so on the 1st of January I went and found all the ones that didn't go off and made new fireworks," he says.

"I'm intrigued also with the large scale of it."

So is he anxious about how things will go on Monday?

"No, not any more - I think it's going well," he says, although he admits there was some early worry about budgeting the project.

"I had budgeted my whole design pretty okay, but we discovered that when we tried to put it out for tender, it turned out that the big companies who come from Sydney or Melbourne who can do that kind of stuff were going to bring all their own people with them, so they had in their fee already something like $80,000 just for hotel costs, so we could not work with them," he says.

He said this approach went against Archer's ethos about involving local people in the project, to create a skill-based legacy long after the day was over.

The result has been that Ruigrok van der Werven and the team have more or less managed the project in-house, and used local staff and experts where possible.

For example, the catamarans bearing the letters will be driven by young members of the Canberra Yacht Club, who are certified motorists.

Ruigrok van der Werven said while he had worked on many large-scale projects, this one was unusual because he was working with government.

"It worked okay. I'm a freelancer, and I normally work for other theatre companies, for festivals," he says.

"But I'm a theatre man and this is a festival, and both the directors are theatre people."

The March 11 party, entitled Canberra In So Many Words, will be focused around Lake Burley Griffin and kicks off at midday, with events winding their way clockwise around the lake through various sites, ending up at Regatta Point with live rock bands playing until 11pm.

For more information, visit www.canberra100.com.au.