The author now has 20 books to his name and will address Australia's first Older Person's Assembly as a keynote speaker at the end of the month.

The 78-year-old Canberra-based writer hopes to use the opportunity to share his thoughts on growing older.

''I have this theory we live through three distinct sections of our lives,'' he said.

''The first is that disastrous section called growing up, then the second third is that travesty we call marriage, children, mortgages, struggle and anxiety and then suddenly someone says you have enough superannuation. It's that third stage you need to watch very carefully, it's time to do all those things you couldn't do in the other stages.''

Mr Courtenay said he despaired for people who spent their older years playing golf.

He said he would rather sit down and write than ''chase a white ball across a green field and into a hole''.

Mr Courtenay moved to Canberra three months ago and already loves his new community. ''I have this thing where I say good morning to everyone, but in Sydney only one in 16 responded. I did the same thing in Canberra when I arrived, and I got a 97 per cent reply. Now that tells you something.''

The Older Persons Assembly will be held in the ACT Legislative Assembly on September 30.

Minister for Ageing Joy Burch said the event would bring older Canberrans together to discuss how the city could become more age-friendly.

''We are inviting Canberrans into our space of decision making to see what they think we need to do next,'' she said.

''We will wrap the day around Canberra as an age friendly city.''

Ms Burch said support services, housing and transport were issues likely to be canvassed at the all-day event.

''It's about looking at these issues through a new lens to make sure we get it right.''

More than 140 Canberrans applied to be government-appointed delegates, but because of seating restrictions only 70 delegates, ranging from 55 to 89 years of age, were chosen.