Forced to endure months in COVID-19 lockdown, most young Australians have come away feeling lonely and left out.

The majority of 12- to 25-year-olds feel isolated from others, according to headspace's national youth mental health survey released on Tuesday.

Sixty per cent of young people lack companionship, while 62 per cent report feeling left out.

Feelings of isolation were higher among LGBTIQ+ youth (77 per cent) and those living in regional areas (62 per cent).

While COVID lockdowns ended a year ago, headspace chief executive Jason Trethowan said they were still having an impact.

"We're finding many young people are still feeling cut off from the world and struggling to re-establish relationships," he said.

While the festive season could be a difficult time for the young, Mr Trethowan noted they weren't alone.

"There are people waiting to help," he said.

"Talk with someone about how you're feeling, whether that's a family member or friends or a professional service like headspace."

Lifeline is also preparing for its busiest time of the year, with the service ready to support up to 4000 people each day between Christmas and New Year's Eve.

Chief executive Colin Seery said more crisis supporters were working to respond to calls and messages throughout that period.

"The idea of togetherness traditionally associated with holidays can also exacerbate the intense loneliness many people feel," Mr Seery said.

Parkrun is also staging more than 160 events across the country on Christmas Day and New Year's Day so people don't feel isolated.

Participants are encouraged to pull out their best Santa costume or festive outfit for the community-based walk, jog or run outings.

"For some participants, Parkrun will be the only place they'll get a chance to speak to someone on Christmas Day," health and wellbeing manager Glen Turner said.

Parkrun hosts around 50,000 participants looking to get connected and energised at more than 400 locations across the country every Saturday morning.

Lifeline 13 11 14

beyondblue 1300 22 4636

Kids Helpline 1800 55 1800 (for people aged 5 to 25)