WING Lung Bank reported a 21 per cent increase in 1993 profit to $472.8 million from $391 million in 1992, owing to a steady growth in business. Earning per share rose from $3.49 to $4.22. A final dividend of $1.32 was proposed. Coupled with the interim dividend of $0.40 per share, total dividend for last year would be $1.72 per share. The bank said it plans to increase its capital from $800 million to $1.2 billion and a bonus issue will be made of one new share for every five existing shares, with about $111 million taken from the general reserve for that purpose. It proposed that $220 million be transferred to the general reserve. During the year, total deposits grew by 20 per cent to $26.3 billion. Other operations such as loans, foreign exchange, bills, insurance, trustee and securities broking services also showed a satisfactory rise, the bank reported. Total assets increased by 20 per cent to $28.2 billion. The bank spent $100 million to buy a computer system. ''With the adoption of more advanced technology, and the improvement of system capability, it will be in a better position for new products development,'' the bank said.