Dressed in a 100-year-old samurai outfit made of Japanese hemp, performance artist Mai Ueda serves organic tea mixed with iced watermelon juice to four visitors at a time in a tearoom on the roof of the National Gallery Singapore.

The small, air-conditioned bamboo enclosure - designed by Argentina-born Thai artist Rirkrit Tiravanija - on the Ng Teng Fong Roof Garden Gallery is the heart of a new art installation commissioned by the National Gallery.

The work, which is named untitled 2018 (the infinite dimensions of smallness), will show here until Oct 28. To reach the tearoom, viewers first walk through a 4m-high, 15m-wide and 19m-long maze made of bamboo poles lashed together.

It can take a minute or an hour to reach the centre. The twisting path made by browning bamboo poles invites visitors to interact with one another and take plenty of selfies on the rooftop space.

Tiravanija, who is 57 this year, said at a media preview on Tuesday (Jan 23): "I like to make work where I don't have to tell people what to do. I want people who come to just be themselves."

The artist blurs the lines between art and everyday activities in his practice. An early work in the 1990s saw him cook and serve curry to visitors. In 1992, he constructed a teahouse stocked with leaves, so viewers could brew their own tea.

In 2013, Ueda performed the tea ceremony in a mirrored tearoom created by the Thai artist. She will serve tea at the rooftop tearoom to visitors this weekend and then train volunteers who will hold tea ceremonies in the installation on the first Sunday of every month, until October.

Tiravanija says: "I look at tea and coffee as a medicinal elixir." He cites a legend where a monk's robe was used to create an enclosure to shelter the Buddha as he served tea to followers.

Alongside this spiritual theme is the use of an everyday construction material, bamboo, which the artist sees used for everything from floor mats to building scaffoldings in Thailand. About 2,500 bamboo poles were flown over from his home, Chiang Mai, to create the installation. "It's a material I feel is part of my own structure," says the artist.

While designing the installation, he considered its location: a rooftop exposed to sun, rain and humidity. "So I thought of how to make a shelter for whoever will come and spend time there," he says. "The exhibition is in a public space and needs to be made in a way that the public can spend time with it."