The government of the Hong Kong Special Administrative Region has cracked down on cross-border parallel trading in infant milk formula to ensure local stores don't run out of stock. The new regulation, starting from March 1, allows a person leaving the city to carry a maximum of two cans, or 1.8 kilograms, of infant formula. Such a person has to be aged 16 years or above and must not have left the city in the last 24 hours. And though offenders face a fine of up to HK$500,000 ($64,469) and two years in jail, 45 people were detained for violating the limit on the first two days of the month alone.

Also, just before Spring Festival, Hong Kong's subway operators reduced the weight of carry-on luggage on trains, from 32 kg to 23 kg, to curb cross-border parallel trading to allay city residents' fears that local stores would run out of infant milk formula.

The two-can limit has become the subject of discussion even at the ongoing annual sessions of the National People's Congress and the Chinese People's Political Consultative Conference.

Many Hong Kong residents have welcomed the new measure, while others say it would harm the city's image as a free market. But a large number of Internet users on the Chinese mainland have criticized the Hong Kong administration for taking a "draconian measure" while expressing concern over the safety of products made by domestic dairy companies.

The development reminds us of the hullabaloo over a Hong Kong resident stopping a mainland mother from feeding her daughter instant noodles in a subway carriage about a year ago. The incident saw Hong Kong residents and their mainland compatriots exchanging heated words, topped by the fiery remarks of a Peking University professor.

Though such incidents reflect the gulf that still exists between mainland and Hong Kong residents, they will not reverse the process of Hong Kong's total integration with the mainland. Instead, they will help highlight the problems that need to be solved in the short as well as long term.

My nephew, who is now 6 years old, has never had mainland-made baby formula. Like many parents in Guangdong province, my cousin used to travel to Hong Kong and Macao almost regularly to buy imported milk powder, and my family members in Hong Kong were always happy to carry some whenever they visited their hometown.

Apart from the price difference and, more importantly, the confidence in the products imported by Hong Kong, now mainlanders are also using their growing purchasing power and a stronger yuan to lengthen their shopping lists in the city.

In the early days after Hong Kong relaxed travel restrictions for residents of some mainland cities, mainlanders visiting the city mainly went for electronics, jewelry, cosmetics and branded clothes. But nowadays, Hong Kong's shopping streets and even pharmacies are packed with mainland tourists, who lap up a wide range of daily necessities, from shampoo, detergents and soybean sauce to diapers and toilet paper, even though many of the products are actually made on the mainland. This should send a message to the country's quality watchdog.

Responding to journalists' questions on Hong Kong's new measure, China's top political advisory body spokesman said 99 percent of mainland-made milk formula meet the country's quality standard. He added that lack of faith is forcing mainland customers to make a beeline for dairy products in Hong Kong.

Mainland customers are not in the least to be blamed for lacking confidence in some mainland-made products given the series of scandals around contaminated dairy products. The craze to buy imported milk in Hong Kong is a side effect of the scandals, which is more than what the region of 7 million people with a land area equal to only one-fifteenth of Beijing's and limited supply can handle.

The heated argument on the two-can limit reflects the negative feelings mainlanders and Hong Kong residents still have against each other. Many mainlanders criticize Hong Kong residents for their "false sense of superiority" and their "antagonism" toward mainland tourists. Hong Kong residents, on the other hand, blame mainlanders for the increasing pressure on the city's housing, education and medical systems.

Indeed, integration with the mainland has created unprecedented opportunities for Hong Kong. But it seems to have progressed steadily only on the economic level but beyond the city's infrastructure capacity and supporting measures.

With tourism booming, many community-based stores hidden in between Hong Kong's skyscrapers, which represent the collective memory of local residents, are being forced to relocate or even close down as retail giants grab space for new stores or to refurbish the old ones to sell goods that are popular with mainland buyers.

Such developments are not restricted to Hong Kong. On a trip to Macao during Spring Festival, I was stunned by the city's development in the past few years - the rapid expansion of casinos and new high-rise apartment buildings. But I was frustrated waiting for hours to cross the border at night because Macao, home to just 576,000 residents, received more than 400,000 visitors, mostly from the mainland, on the first three days of the weeklong Spring Festival holiday.

Comprehensive integration is an irreversible trend, but it demands concerted efforts from both sides, and accusations will do little good to either side. When such arguments flare up, it would be wise to cool them down by using reason and boosting mutual understanding.