The US fast-food giant was forced to suspend online sales of the plush toys just 80 minutes after their launch on Wednesday, resuming only hours later to the chagrin of die-hard collectors.
The Hello Kitty Bubbly World Collector's Set -- comprising six versions of the mouthless kitten, dressed as different animals -- are making their global debut in Singapore and have been released to mark the 40th anniversary of the iconic character.
A dedicated McDonald's website for sales of the dolls was functioning normally Thursday after the servers were fixed, but many still vented frustrations over problems with completing payment.
"Are you selling Sanrio plush toys or disappointment?" asked Jasmine See on the McDonald's Singapore Facebook page, referring to the Tokyo-based company behind the Hello Kitty industry.
"If your servers cannot support such heavy Internet traffic why start such a marketing strategy?" asked Desmond Chua.
The online mayhem comes less than a year after a sale of the kittens in skeleton outfits sparked chaos in McDonald's outlets across Singapore, with police called to at least one branch amid rampant queue jumping.
Some Singaporean fans are obsessed with obtaining the entire Hello Kitty collection, at times paying exorbitant rates for dolls resold online.
A complete set of the new "Bubbly World" dolls costs Sg$80 ($64) and comes with meal vouchers as well as a special commemorative certificate. The toys will be sold at McDonald's restaurants across Singapore from Monday.
Bids for a set of the new toys were as high as Sg$180 on eBay Singapore on Thursday.
Hello Kitty, which started in 1974 in Japan as a moon-faced cartoon cat on a coin purse, has developed into a global cultural phenomenon.
Sanrio says it now has around 50,000 different products on sale in 109 nations and territories.
Kitty mania is also well established in Hong Kong, with both men and women lining up for hours outside McDonald's outlets during past promotional schemes.
In 2008, Japan appointed the character as its goodwill tourism ambassador to China and Hong Kong.(AFP)
