UNTIL yesterday, the most visible sign of the Bank of China's growing influence and presence in Hong Kong has been its imposing headquarters which dwarfs the Hong Kong Bank and the Standard Chartered Bank and towers over the tiny Legislative Council nearby. Now, the Bank of China will be noticed wherever money changes hands. And, Hong Kong being one of the greatest commercial centres of the world, that means a lot of attention. Some may worry that the bank's debut as a note-issuing institution three years before Hong Kong reverts to Chinese control is a sign of mainland political intrusion into a territory still under British rule. Certainly it is a re-affirmation of China's intention to resume sovereignty over Hong Kong on schedule in July 1997, come what may. But, for most businessmen, the note issuance is a token of the rapid integration between the Chinese and Hong Kong economies and proof that Beijing cares enough about the territory's prosperity and development as a commercial hub for southern China. For along with the prestige it earns from becoming the territory's third note-issuing bank, the Bank of China is also carrying an enormous responsibility and obligation. The obligation is the easy part. Matching its new notes dollar for dollar with US currency deposited with the Exchange Fund is an expensive enterprise. The hard part is fulfilling the responsibility for maintaining a healthy and well balanced economy. It has always been true that when China catches cold, Hong Kong sneezes. But the moment China assumes responsibility for a portion of the territory's currency, it is committed to preserving the health of Hong Kong's economy as well as its own. That Beijing is prepared to demonstrate that commitment so visibly at a time when it is locked in a bitter dispute with Britain over the issue of political reforms is, paradoxically, the all-clear signal for the 1997 economic express. The new notes are a token of China's intention, as far as possible, to separate politics from economics. Lu Ping, the director of the Beijing's Hong Kong and Macau Affairs Office of China's State Council, has made a point of coming to Hong Kong for this momentous occasion, but refused to meet the Governor, Chris Patten. Similarly, China believes it can get on with the business of building economic links with its future Special Administrative Region without first mending its ties with the departing British. Britain, for its part, has chosen not to hinder the establishment of ever-tighter economic links with the mainland. It takes with the utmost seriousness its obligation under the Joint Declaration to maintain stability and prosperity in the territory during the transition to Chinese rule. For an indication of the Hong Kong Government's open-arm acceptance of China's role in preserving the stability of the local currency and economy, one need only recall the words of the then-secretary for monetary affairs, David Nendick, in January last year when the date was set for yesterday's issue. Declaring that the move dispelled any uncertainty about 1997, he said: ''It clarifies issues in relation to 1997, because this is something being resolved in 1994 . . . in a way which quite clearly leads to a smooth transition.'' And yet, as 1997 moves closer without final agreement on Hong Kong's new port and airport developments, with a series of aviation agreements still awaiting China's approval and a number of vital economic matters still unresolved in the Sino-British Joint Liaison Group, the notes issued are also a reminder that actions still speak louder than words. For all the good intentions the new notes signify, it is only a speedy agreement on these key economic issues that will prove both sides sincerely wish to separate their common economic interests from their political differences.