New Zealand was struggling to meet a self-imposed deadline to remove tainted baby formula from shelves worldwide Wednesday and end a botulism scare that has triggered global recalls.

Both the government and dairy giant Fonterra said earlier this week they hoped to ensure the last of the contaminated formula was out of circulation by late Wednesday, but ministers have since warned they can offer no guarantees.

About 90 percent of the product, which was distributed from China to Saudi Arabia, has been collected and Trade Minister Tim Groser said officials were combing Fonterra's records to find the rest.

"It's a question of working through by a process of elimination to find where the last remaining can is... it's really unfortunate, it's just taking time," he told TV3 on Wednesday.

Economic Development Minister Stephen Joyce said the formula had been cleared from New Zealand stores but "internationally there's still some that's being verified, exactly where it is".

"There will be some that's been effectively sold to end users and may or may not be returned," he said on Radio New Zealand.

Joyce acknowledged the botulism scare has dented New Zealand's "clean, green" reputation, particularly in China, where Fonterra has used the country's premium reputation to create a multi-billion dollar dairy market.

"I've read some interesting comments in the last 24 hours, people saying it's not as big as you think, well I beg to differ, it's very significant," he said.

In an editorial that was reportedly widely published in Chinese media, state news agency Xinhua blamed lax regulations in New Zealand for allowing the product to be exported.

It also raised concerns the problems were systemic, pointing to Fonterra's involvement with a Chinese company it part-owned that in 2008 illegally laced milk with the chemical melamine, resulting in six children dying and 300,000 falling sick.

There have been no reports of illness in the latest scare but Groser said such sentiments in one of New Zealand's major export markets were "not pretty".

"I have a very firm view that this is not going to be won by a slick PR campaign," he said.

"The number one thing is to fix the immediate problem. That will determine our real ability to recover our position."

Source: AFP