Since the much-anticipated exhibition by avant-garde Japanese artist Yayoi Kusama opened at National Gallery Singapore last Friday, tickets have been selling fast.

But art lovers are not just rushing to see the 88-year-old's works.

They are also snapping up locally designed merchandise for the exhibition, which have been flying off the shelves of the museum's shop, Gallery & Co. Some items sold out in the first two days of the show's opening.

The exhibition, titled Yayoi Kusama: Life Is The Heart Of A Rainbow, is on until Sept 3. It showcases more than 120 of her works from the 1950s to the present.

The exclusive items include enamel pins, tote bags, pouches and enamel crockery - all splashed in Kusama's iconic motifs such as polka dots, pumpkins and trippy shapes. Prices range from $2.90 for postcards to $36.90 for a foldable umbrella.

The design team of three behind the products are from branding and design studio Foreign Policy Design Group, a co-founder of Gallery & Co. They are creative director Yah-Leng Yu, art director Aurial Lee and designer Hafizah Jainal.

Beefing up the selection of merchandise are items such as T-shirts from the artist's Yayoi Kusama Inc company in Tokyo. Gallery & Co says these are selling well too.

As the official museum store, Gallery & Co has exclusive rights to produce merchandise for every exhibition at National Gallery Singapore. For this show, the designers worked with the museum's curators and project managers from Yayoi Kusama Inc to decide what products to put out.

Ms Lee says the team expected a good response to the merchandise, given Kusama's influence and popularity, but the unexpected buying surge has been "overwhelming".

While National Gallery Singapore declines to reveal visitor figures for the show to date, Gallery & Co says this has been the best-selling series across all the in-house merchandise it has done.

Ms Lee puts it down to museumgoers wanting something to remember a good exhibition by.

"Owning a piece of her 'work' through merchandise has definitely become the new way to consume art," she says. "Kusama has reached cult status, so to own her merchandise is like owning a classic."

And Kusama fans can expect more. Next month, the shop will add more products to the line-up, including socks made in collaboration with Singapore creative studio and gallery shop Supermama and new designs from Yayoi Kusama Inc.

For now, Gallery & Co is restocking the items in stages and doubling initial order quantities.

Those who cannot get their hands on a particular item can place preorders at the museum and collect it another day.

The products can also be purchased from Gallery & Co's website and will be shipped to buyers.

Many die-hard fans could not wait until the exhibition was launched to get their hands on the merchandise and pre-ordered on the website on June 2, a week before the show opened.

Mr Mark Siow, 48, an assistant manager in a bank who has bought other products from her exhibition in Tokyo, spent about $300 on bowls, mugs and pins.

He says: "I got excited when I saw Gallery & Co's products on Instagram. It did a good job of interpreting Kusama's designs. It's a good thing I pre-ordered the products online. If not, I wouldn't have stood a chance of getting any on opening day."

Fellow creatives also gave the designers the thumbs-up.

Advertising veteran Pann Lim snapped up umbrellas and a mug. He plans to give some to friends.

"I like the work. The merchandise are well-produced, of good quality and on a par with other Kusama merchandise. I'm not surprised things are sold out."

Five best-selling Yayoi Kusama merchandise at Gallery & Co

1 Life Is The Heart Of A Rainbow Square Sling Bag ($28.90, above)

This bohemian-looking bag features the painting, Life Is The Heart Of A Rainbow, from the My Eternal Soul series, which has been ongoing for the last eight years.

2 Eye Enamel Pin ($12.90, above)

The eye motif is extracted from Kusama's Love Forever black-and-white series, which the artist drew in marker ink from 2004 to 2007. Gallery & Co also sells five other pins, including three motifs from her My Eternal Soul series.

3 Pumpkin Enamel Rice Bowl ($29.90, above) and Mug ($24.90)

Enamel homeware, a familiar item in many Asian households, gets the Kusama touch too.

4 Song Of A Manhattan Suicide Addict Series Postcard ($3.90)

Take home a piece of the Doyenne of Dots with postcards that feature film stills from Kusama's video installation, Song Of A Manhattan Suicide Addict.

This postcard (above) features Kusama, with her flaming-red bob, against a background of polka-dotted tentacles, and words from a poem.

5 Pumpkin Foldable Umbrella ($36.90, above)

Kusama's signature yellow polka-dotted pumpkin motif turns the functional umbrella into a fashionable accessory.