The upcoming vote on health care is seen as a litmus test for US President Donald Trump Getty, iStock

All Asian stock market were trading higher on Thursday (23 March), with the Shanghai Composite up 0.31% at 3,255.13 as of 5 am GMT, following positive Wall Street performance overnight.

On Wednesday, both the S&P 500 and the Nasdaq Composite closed higher, up 0.19% and 0.48%, respectively. The Dow Jones industrial average, however, fell but by a marginal 0.03%. Asian stocks were said to be taking cues from the steady performance.

Investors remain concerned over the key health care vote in Congress, which is due later in the day. The House is expected to vote on Speaker Paul Ryan's health care plan which has been proposed to replace the 2010 Affordable Care Act, also known as Obamacare.

While President Donald Trump has been calling for repealing Obamacare, the move faces a lot of resistance not just from the Democrats, but also from conservative GOP members.

"The vote on Obamacare is a litmus test for Trump. If he can't push through the bill, it would further damage stocks. It also raises the risk of his other policies, like tax cuts, being delayed," Masafumi Yamamoto, chief forex strategist at Mizuho Securities, was quoted as saying by Reuters.

Moreover, market participants are said to be worried that the delay in repealing and replacing Obamacare could lead to a delay in tax reform, deregulation and government spending.

Apart from this, investors were concerned over the terror incident in London on Wednesday.

In Asia, investors are said to be keenly awaiting a rate decision from Taiwan's central bank with a majority expecting the bank to keep rates on hold.

Indices in the region were trading as follows at 5.36am GMT:

Hong KongHang Seng Index24,322.37Up0.01%
JapanNikkei 22519,070.39Up0.15%
South KoreaKOSPI2,175.40Up0.33%
AustraliaS&P/ASX 2005,708.00Up0.41%

On 22 March, the FTSE 100 closed 0.73% lower at 7,324.72 while the S&P 500 index closed 0.19% higher at 2,348.45.

Among commodities, oil prices gained after touching their lowest levels since November. As of 1.28am EDT, WTI crude oil was up 0.79% at $48.42 (£38.78) a barrel, while Brent crude was trading 0.77% higher at $51.03 a barrel.