Noting Port Arthur anniversary 'important'

Plans to mark the 20th anniversary of the Port Arthur massacre will help the ongoing recovery process, says a psychologist with lasting links to the event.

Dr Rob Gordon has just wrapped up a visit to the Tasman Peninsula where he ran a series of community sessions.

"There is clearly still a need in the community to be talking about this and to be sharing thoughts," he told AAP on Thursday after the last of his open-invitation forums.

In the aftermath of the massacre the Victorian trauma specialist was brought in by the island state's government to help co-ordinate counselling and support networks for survivors and emergency service workers.

He returned on Wednesday at the request of a neighbourhood group.

"Recovering from an event like this is really a life-long process," Dr Gordon told the intimate gathering.

But he added it's important not to avoid talking or thinking about the events of April 28, 1996 when 35 people were shot dead and 23 others were injured.

"If people avoid, they can never put it in the past.

"If we can help people reflect on and talk about the traumatic event that doesn't evoke more pain, then in the course of that talking ... it starts to recede into the past."

Authorities have planned a service at the Port Arthur Historic Site and also at Hobart's St David's Cathedral to mark the anniversary.

John Howard, who was prime minister at the time and as a result of the massacre introduced tighter gun laws, will attend the service.

Dr Gordon conceded that it will be an emotional time for some people.

"Inevitably it will bring some things to the surface," he said.

"I would encourage a sense of diversity - the anniversary can be helpful if people are allowed to do it in their own way and are respectful."

Hobart man Martin Bryant is serving 35 life sentences after pleading guilty to killing 35 people.