Asian and European stock markets mostly rose Friday hours before a much-anticipated speech by US Federal Reserve boss Jerome Powell that could shed more light on expected interest-rate cuts.

The dollar fell against other major currencies including the yen, which strengthened after Bank of Japan chief Kazuo Ueda signalled that Japanese rates could rise again.

Investors have been on tenterhooks all week ahead of Powell's address at the annual symposium of central bankers in Jackson Hole, Wyoming, on Friday.

Powell has already indicated that a reduction could come as soon as September, but traders want to hear fresh signals from the Fed chief following a slew of data that raised recession fears and rocked the markets earlier this month.

The Fed has kept its rates at a 23-year high after raising them in efforts to combat inflation, which has cooled, while central banks in Europe have started to cut theirs.

Speculation is rife about how big, or small, the first US cut might be. Most analysts expect a reduction of a quarter-percentage-point but some traders hope for as much as half-a-point. 

"For investors, the big question is to what extent Powell validates expectations for a September rate cut, and whether he offers any indication of how big any rate cut might be," said a Deutsche Bank note.

Powell's speech comes after three Fed officials said they wanted to see more data before agreeing to a rate cut.

Ipek Ozkardeskaya, senior analyst at Swissquote Bank, said Powell "is expected to douse the jumbo rate cut expectations because there is no reason for the Fed to start cutting the interest rates by big chunks in the absence of a severe economic slowdown, market stress, or a crisis."

Data released this week showed a robust US services industry but also a rise in jobless claims and a cooler-than-expected labour market.

European markets were up in midday trading while Asia finished mixed, with Tokyo and Shanghai in the green and Hong Kong in the red.

Wall Street's three main indexes ended in the red on Thursday.

BOJ hike signal

While other major central banks are easing their rates, the Bank of Japan made its second hike in 17 years in late July, a move that caused the yen to rise and contributed to a market rout.

Ueda told Japanese lawmakers on Friday that the BoJ could hike rates again if inflation and the economy performed as expected, and the yen rose against the dollar following his remarks.

A stronger yen makes it less attractive for investors who use the cheaper currency to buy higher-yielding assets such as stocks, a practice known as "yen carry trade".

The last rate hike caused investors to rollback such trades.

In company news, shares in Alibaba rallied after the Chinese e-commerce giant said it would upgrade its Hong Kong-listed shares to primary status, opening it up to China's huge army of investors.

In Europe, Nestle shares fell after the surprise exit of its chief executive, Mark Schneider, following slowing sales and negative headlines at the Swiss food giant.