PROPERTY group Hon Kwok Land Investment saw turnover dip slightly but interim profit fall by a much wider margin. Turnover was off 3.4 per cent to $283.7 million but after-tax profit before minority interests plummeted 30 per cent to $91.09 million from $128.73 million. Nevertheless, directors are keeping the interim dividend to the 1992 level of 3.5 cents a share, even though basic earnings per share dropped to 13.4 cents from 22.1 cents. Hon Kwok Land said it was confident profit for the full year would increase markedly over previous years. Chairman James Wong Sai-Wing said: ''In the absence of unforeseen circumstances, profits for the full financial year ending March 31, 1994 is expected to increase substantially over those for the previous years.'' He said because of the scarcity of land in Hong Kong, low interest rates and China's rapid economic growth, demand for residential, office and commercial properties, especially in Causeway Bay, Tsim Sha Tsui and Yau Ma Tei, would improve in the coming years. The group also said yesterday it would guarantee a US$50 million issue of 4.875 per cent convertible bonds due 2000. The bonds, in denominations of $10,000, will be convertible from January 31, 1994 to December 8, 2000 into equity at an initial conversion price of $4.25 a share. The initial conversion price is equivalent to a premium of 20 per cent to the average closing price of $3.54 for the five trading days to last Tuesday. The subscription agreement for the bond issue was signed by Hon Kwok with several managers. Besides Nomura International, the others include Baring Brothers, Morgan Stanley International, ABN-Amro Securities (Far East), Jardine Fleming and Crosby Securities.