Singapore has taken top spot for the highest level of cross-border investment in the Asia-Pacific, according to research from global real estate services firm DTZ.

The top ranking covered the period from the third quarter of last year to the second quarter of this year, the DTZ report said. The Republic was also the third-highest investor in North America.

DTZ's South-east Asia chief executive Ong Choon Fah said: "Singapore-based institutional investors have been exploring overseas opportunities to earn higher returns, and for portfolio diversification. Additionally, Singapore's stable currency helps investors lower the cost of investments, especially in the Asia-Pacific."

The report did not provide a figure for Singapore's level of investment in the region, although a chart indicated that it was approaching US$5 billion (S$ 7 billion).

DTZ also found that global investment in commercial real estate shot up 15 per cent in the first half of the year to US$318 billion from a year earlier.

However, this was rather uneven across global markets, with activity in the Asia-Pacific slowing down 7 per cent to US$90 billion.

The reasons for this slowdown may include a lack of suitable products in some markets, and a mismatch between buyer and vendor expectations around the region, said Dr Dominic Brown, head of DTZ's Asia Pacific Research.

In comparison, investments in Europe and North America continued to grow steadily, with European volumes rising 23 per cent to US$274 billion, and North American volumes up 18 per cent, over the same period, to US$311 billion.

London remains the leading city for attracting cross-border capital, with over US$39 billion transacted in the 12 months ended June 30. That is 7 per cent higher than a year ago.

In Asia, Tokyo - at US$18 billion - was the most traded market and fourth-largest globally.

Sydney was ranked second in the Asia-Pacific and 10th globally, with US$8.2 billion traded, up more than 15 per cent on last year's figure.

Looking ahead, commercial real estate will continue to remain attractive to investors, especially given the low interest rates and bond yields in many markets across the globe.

Mr Nigel Almond, head of DTZ's Capital Markets Research and author of the report said: "Despite prime yields edging towards new lows in many markets, the attractiveness of real estate remains in the low interest rate environment.

"Continued demand for real estate will see global investment volumes this year increase by 22 per cent to reach levels close to their previous 2007 peak of US$791 billion."

London remains the leading city for attracting cross border capital, with over US$39 billion transacted in the 12 months ended June 30.