A LEAP of almost 50 per cent in property deals points to a resurgence of speculation in homes and has prompted suggestions that the Government might review the mortgage loan ceiling. The Land Registry was notified of 18,881 building unit deals last month, 47.4 per cent more than in June, and 49.8 per cent more than in July last year. Most of the deals involved residential flats. July's deals totalled $55.8 billion, against $43.4 billion in June and $30.5 billion a year earlier. The Land Registry said deals at big developments in Ma On Shan, Sham Tseng, Tsing Lung Tau and Fanling had been mainly responsible for the surge in activity. S.G. Warburg director Michael Green said last month's sale and purchase agreement total was the fourth-highest, behind the 20,910 in October 1991, the 20,600 in April 1991 and the 19,161 in May 1992. The Land Registry also reported a jump in the number of land deals, from 339 in June to 402 last month. Sales volume rose 47.2 per cent, from $9.5 billion to $14 billion. Morgan Stanley research director Peter Churchouse said he was surprised by the sharp jump in building unit deals. He said it clearly indicated that the speculative nature of the homes market had not died. Mr Churchouse said the higher figures could force the Government and the banks to look again at the mortgage loan ceiling, now 70 per cent for most residential units and 60 per cent for luxury units. ''These are very interesting numbers and I think it's going to generate some concern on the Government's part and on the part of the banks that they might want to crunch down on things a bit.'' he said. Some banks have already started to act. Earlier this month, Standard Chartered Bank attempted to cool the demand for mortgage loans by increasing charges to applicants and making stricter assessments of borrowers' ability to repay. The decision reflected the bank's concern about the increase in residential prices, and dampened hopes for the relaxation of the 70 per cent mortgage limit, introduced in October 1991. Some in the industry believe the mortgage ceiling has helped curb speculation. Property consultant A.G. Wilkinson & Associates argues that the Government is fuelling speculation and that many punters are snapping up property in anticipation of an eventual relaxation of the ceiling and a rush on the market. Warburg's Mr Green said last month's strong sale and purchase agreement total was not necessarily indicative of the market in general. He expected the total to tumble over the next few months to about 10,000 units a month. Mr Green said his firm believed prices would rise by four to 10 per cent this year and climb to about the rate or inflation or slightly higher in 1994. He said low interest rates, buoyant economic growth, and high rental increases made the market a good one for buyers. ''I think it's a healthy investment for people buying units in which to live,'' he said. ''It's a form of contractual savings, a hedge against rental inflation and gives you the security of tenure.'' The Land Registry said there had been seven major building mortgages and 15,564 other mortgages received for registration last month, compared with one building mortgage and 18,296 other mortgages last July. New building mortgages totalled $380 million last month, compared with $50 million a year earlier. The Land Registry said that because several huge mortgages had been submitted for registration last month, the total amount secured under new mortgages other than building mortgages had climbed by 131.9 per cent to $16.91 billion.