[TOKYO] Tokyo stocks opened higher on Wednesday helped by a cheaper yen and rallies on Wall Street, but investors remained cautious ahead of the US State of the Union address.

The benchmark Nikkei 225 index was up 0.39 per cent or 82.24 points at 20,926.69 while the broader Topix index edged up 0.28 per cent or 4.47 points to 1,587.35.

"Following rises in US shares, Japanese shares are seen starting on a positive note, and the focus will be on whether the Nikkei 225 can reach the level of 21,000," online brokerage Monex said in a commentary.

The dollar fetched 109.90 yen in early Asian trade, little changed from 109.97 yen in New York late Tuesday but was stronger than below 109 yen levels late last week.

US President Donald Trump will deliver his State of the Union address during Tokyo trading hours and "expectations are for the President to make comments on North Korea, the US economy, China trade talks and border security," Rodrigo Catril, strategist at National Australia Bank, said in a note.

"The latter of course is the main focus for markets given that Trump has hinted at the possibility of declaring a national emergency... in order to fund his much desired wall along the Mexican border," he added.

"The political ramifications from such an announcement... could rattle markets," Mr Catril said.

In Tokyo, Panasonic was up 3.33 per cent at 1,069.5 yen and Olympus was up 1.31 per cent at 4,625 yen.

Small car specialist Suzuki was down 1.92 per cent at 5,643 yen after its third quarter operating profit was lower than market expectations.

SoftBank was up 1.80 per cent at 8,568 yen ahead of its nine months to December earnings reports due later Wednesday.

AFP