The Knight Frank Asia-Pacific Prime Office Index rose for the twelfth successive quarter, boosted by the Chinese economy and the knock-on effects from Japan's stimulus measures, the real estate service provider said in a report.

The index increased 1.7 percent in the first quarter of 2013 and 5.6 percent over the last 12 months, as the still robust economy in China is likely to boost activity across the region, with domestic occupiers leading demand for prime office space, the report showed.

Meanwhile, 15 of the 19 prime office markets tracked by the index across the region saw prime rents increase in the first three months of 2013.

Tokyo led the ways in rental growth, where Grade-A office rents increased over the quarter by nearly 16 percent.

Rents are expected to soften in only three of the 19 markets monitored over the next 12 months, the report showed.

Thomas Lam, director and head of research & donsultancy, greater China at Knight Frank, remains positive about the long-term outlook for premium and Grade-A office buildings in Hong Kong.