Chinese officials have repeatedly claimed that infant formula products in the country are safe following tighter regulations in recent years in the market, in a bid to revive the shattered industry which was hit by a string of chemical-tainted milk scandals.

In the latest effort, a vice chairman of China Dairy Industry Association told the state-run People's Daily that results of 11 sampling tests in 2012 found no problems respecting quality in major brands of infant formula products.

"The products are 100 percent up to national standard," said Liu Meiju, "Consumers can rest assured". Her words were delivered at a time when mainland parents, desperate for untainted baby formula, wiped out supplies in Hong Kong, provoking restrictions on baby milk exports and detentions of dozens of travelers.

Liu said China has tightened regulations to control quality since 2011, including a monthly sample test plan across the country, and stepped up information disclosure.

Following years of crackdown and regulations, there is "a change in essence" in the quality of home-made milk products, said Liu, "We hope people can take another look at home-made milk products in the light of development".

She added that China has applied relatively high quality criteria on milk products, compared with other countries.

At least six babies were killed and other 300,000 were sickened after consuming infant formula contaminated with the industrial chemical in 2008. Similar scandals continued to hit China's milk industry in latest years.

Lv Xinhua, spokesman for the first session of China's CPPCC, the top advisory body, told reporters during the two sessions that 99.1 percent of milk power meets national standards, citing statistics from the country's quality watchdog.

His remark was met with criticism and doubts over its credibility after dominating Chinese media for days during March's annual gathering of elites in the country.

Cui Yongyuan, a famous anchorman from China Central Television for his outspokenness, said he has no confidence in mainland-manufactured formula milk when asked by a journalist to comment on the 99 percent claim. "How would I know where the 1 percent is?" he told reporters.

The remaining 1 percent would be recalled in a timely way, or disposed even before leaving factories, the People's Daily quoting an industrial official as saying.