BUY property in Vancouver, London, New Zealand and Hongkong - but sell in Bangkok and Malaysia. That was the advice of Vigers director Mr Gareth Williams, and, what is more, far from being overheated, he said the Hongkong office market was still going up. ''Investors should forget Hongkong residential at the moment, but the commercial market has got some way to go, and I would aim for strata-title offices if I was looking for somewhere to put my money,'' said Mr Williams. Recalling 1991 when the residential market was going up, while the commercial market was coming down, he said the opposite was now happening. He explained that between late 1991 and September last year, the office market bottomed out, and had seen steady growth since in strata-title office prices. Looking at Singapore, previously unheard of speculation seemed to be creeping into the market. ''I would invest in residential in Singapore because that has started going up. ''I would sell in Bangkok - I think the market has peaked, and is effectively starting to dribble down a bit,'' added Mr Williams. The problem there was the amount of recent speculative developments of up to three million square feet. Bangkok vacancy rates are expected to rise to 35 per cent by the end of 1994. Indonesian residential property was due to show an oversupply of luxury condominiums in 1993. Vigers regional researchers advised that only projects in good locations would sell this year. But Mr Williams was bullish on condos in Canada. ''Vancouver could see a substantial increase in prices over the next two years,'' said Mr Williams. Malaysia looked as though it was a sell situation and take up was not promising. Research showed rentals were being maintained, as people rented instead of buying. On the commercial side, rentals and values had peaked and stabilised, a situation which would probably carry on through this year and next. Australia was split into two sections - Brisbane and the Gold Coast, and the rest of Australia. Brisbane and the Gold Coast were attracting a lot of population movement, pushing up the residential sector. On the other hand, the New Zealand market was interesting. ''Their property market has been showing growth and quite good returns and it's definitely a place to invest in the office sector.'' London was definitely a buy situation at the moment.