John Lyall reaches out with his left hand to shake, a light clasp. A series of strokes four years ago means some of the big installations he used to do are no longer as feasible to achieve, but for an artist whose work has always been concerned with process and ideas, there's still a lot of art he can make.

Lyall has had 37 shows since the strokes. He still does performances, including one in the window of a Queen St bookstore eight days after getting out of rehab, even before he could walk again.

"Obviously I'm not as fast as I used to be. That is a two-edged sword. It means sometimes I can't do what I would like to do, but sometimes it means I have to think about the stuff I do rather more.

"So it isn't always worse. It isn't always better, but it isn't always worse. There's this enforced restraint, and also the work becomes tinged with not quite sadness, but ..." Lyall trails off, looking at the works on the wall.

His new show is a performance, a process, a way to recapitulate a life in art, and a road trip.

It records Lyall and partner Claudia Bell's tour of the South and Stewart Islands last December, making stops at specific sites where Lyall would be videoed tacking up a poster, noting the date and place with his new left-handed writing, then walking away.

Some of the places were familiar from the pair's 1995 book on local claims to fame, Putting Our Town on the Map. Others were new tothem.

The one-off posters were recovered for the show, sometimes battered and stained by wind and rain. A unique larger version of each PDF file, printed on good-quality watercolour paper, is what is offered for sale.

The images are collaged from work Lyall has done around the world, manipulated in Photoshop and Illustrator.

"I was collapsing the world into the South Island and then collapsing the South Island into the Jane Sanders Gallery," Lyall says.

A photo of a moa in a bakery in Korea was taken to Moa Flat in Otago for installation. Beach litter from Busan; an equation drawn in mussel shell pearls on a bed in a Korean love hotel; a mathematical equation walked into the snow at Sarajevo; Lyall in the Queen St window - all these fragments turn up in announcements of apocryphal shows.

A Southland beach became briefly festooned with a scan of a Meccano motorcycle in honour of Burt Munro.

In Cass, Lyall was videoed putting a poster on the railway station featured in the Rita Angus painting. His installation also includes a Des Helmore painting of Cass which does not include the shed. It adds more layers of reference to the palimpsest of New Zealand art.

Lyall says the road trip continues the ethic that he has pursued since his early art-making with Sydney School of Architecture colleagues in a collective calling itself the Bhutanese School of Environmental Sculpture.

"In all my work I tend to take nothing but photographs, leave nothing but footprints," he says, paraphrasing a line from the historic Chief Seattle letter which has been adopted as a green creed.

The prosaic act of tacking a piece of paper to a shed wall can become an elegant rhetorical question through process, intent, image and text.

The coarseness generated by the poster production process was deliberate. "I don't want them to be beautiful because that would upstage the project, because the image would become too important," Lyall says.

"Art's ugly. Art's ephemeral. It always has been, or it has since Marcel Duchamp. Work like this is imbued with the realities of process art ... these works become your way into that process, but have their own artefactual nature, which is as residue."

Lyall says the mainland is a great canvas for a conceptual artist.

"These places in the South Island, which, particularly for North Islanders who don't go to the South Island, they are mythical, they are more spoken about than visited, places like Jackson's Bay, Doubtful Sound, Stewart Island. The point is I went there - this is a road trip."

What: Poster Boy by John Lyall.
Where and when: Jane Sanders Art Agent, cnr Shortland-Queen Sts (open Wed-Sat), to July 10