SINGAPORE, Nov 22 (Reuters) - The world's biggest asset manager BlackRock said on Wednesday it was cautious on equity markets in Asia's financial hubs of Hong Kong and Singapore despite an improving economic outlook for the region.

The fund, which manages nearly $6 trillion globally, said it is underweight versus its benchmark in those two markets as well as Malaysia and Taiwan, while it was most overweight in the emerging economies of China, Indonesia and India.

Andrew Swan, the fund's head of Asian and global emerging markets equities, said Hong Kong's economy remained on a slow growth trajectory.

"We see this (Hong Kong) as a low growth economy still that is not benefiting from what we are seeing globally in terms of the economic expansion in markets like China and elsewhere," Swan told reporters at its 2018 Asia investment outlook briefing.

He said the property market - where prices hit a record high - was a "contentious issue", and he warned broadly about "bubble-like" valuations in the internet sector.

In Singapore, Swan said the fund also had little exposure to firms reliant on growth in the domestic economy.

However, he said he had been increasing investments in the oil services sector, which has in recent years been knocked by a spate of defaults as oil prices tumbled.

Similar concerns about the "flat and unexciting" domestic economy and the IT sector has kept BlackRock away from Taiwan, while in Malaysia Swan said there was little corporate earnings growth and valuations were "very high". (Reporting by John Geddie; Editing by Shri Navaratnam)