Foreign property investors and those considering moving abroad should focus their attention on capital cities to benefit from high demand supply shortages, one expert has advised.Marc Da-Silva, editor at homesoverseas.co.uk, explained that capitals are likely to experience the most acute supply shortages and demand for both rental and resale property.His comments came in response to research carried out by NatWest International Personal Banking which showed that New Zealand has taken the top spot in quality of life rankings among expats.He explained that investors are eyeing a window of opportunity in the New Zealand market."Prices have been falling and, given the fact that interest rates are falling across the globe and certain measures are being introduced, now is a great time to buy," he said. Further figures from the NatWest study showed that 63 per cent of expats left the country with less than £5,000 in the bank. Some 64 per cent now have a net worth of between £250,000 and £1 million.Having a low initial capital may heighten the need to scrutinise foreign exchange rates prior to leaving the country.