The statements - a rare display of co-ordinated action - underline China's fears that the return of Hong Kong's sovereignty will trigger an avalanche of illegal Chinese immigration to its newly recovered territory.
China has gone a step further and announced strict controls on Chinese nationals even being granted the right to visit Hong Kong during the handover period in the middle of the year. Both the colony and the neighbouring Chinese border town of Shenzhen will be the subject of a visitor curb.
Wang Ying-gang, a vice-director of the Guangdong Public Security Bureau was reported by local newspapers as saying that the curbs were being imposed "to maintain Hong Kong's order and ensure the smooth running of the various celebrations being held".
Nevertheless, the authorities have noted an upsurge in illegal immigration, particularly of children, because their parents believe that their situation can be legalised after China takes over on 1 July.
Last month 400 illegal immigrant children gave themselves up to the authorities, some three to four times the normal number.
Police sources say that the "snake heads" - the criminal gangs who smuggle illegal immigrants over the border - are spreading rumours about a possible post-July amnesty in order to stimulate business. They run well organised people smuggling networks using small craft which arrive in Hong Kong waters with illegal immigrants and leave with goods to smuggle into China.
The slightest hint of an amnesty for illegal immigrants triggers an immediate upsurge of Chinese people smuggled across the border. For example, in June 1987 some 40,000 people were prevented from crossing into Hong Kong by the Chinese authorities following an amnesty rumour.
It is not known how many illegal immigrants manage to penetrate the tight security around Hong Kong's land and sea border but every day truckloads of "illegals" are repatriated to China without any right of appeal or a hearing to determine their status.
The Chinese government has stated that even after Hong Kong returns to Chinese sovereignty, there will not be free entry into the territory for the former colony's newly reunited fellow citizens.
Legal immigration to Hong Kong from China will remain restricted to a quota of 150 people per day, or 55,000 people per year, which is slightly more than the number emigrating.
There are numerous reports that the flow of legal immigrants, which is controlled by Chinese officials, is riddled with corrupt practices.
Large sums of money have been paid to Chinese officials to secure a place among the legal immigrants who are supposed to be restricted to those entering to rejoin their families.
The Chinese government knows that there are millions of its people in search of economic betterment who would flood to Hong Kong given even the smallest hint that floodgates were to ease open.