* MSCI world index strains for best streak since 2003
* Asia-Pac index near 10-yr high, Nikkei lurches after high
* Tax plan worries weigh on dollar, kiwi rallies on RBNZ
* Crude oil steadies, gold hovers near 3-week high
* Bitcoin slides 5 percent after latest record high
LONDON, Nov 9 (Reuters) - Another impressive record for world stocks was hanging in the balance on Thursday, as a late blow-out in Japan and falls in Europe and U.S. futures threatened to spoil the longest winning streak for MSCI's global index since 2003.
Japans Nikkei saw a wild 2 percent swing after hitting its highest since 1992 and Europe's main bourses were firmly in the red following a tumble from tech and commodity stocks and as Brexit talks resumed amid low expectations in Brussels.
There were a series of ECB speeches and buoyant new growth forecasts from the European Commission, though bond markets were mostly quiet following a rally this week in benchmark U.S. Treasuries and Bunds.
Germany's 10-year bond yield edged up for the first time in more than a week and the euro and pound were both higher as the long-running saga of U.S. tax reforms weighed on the dollar.
Oil and Middle Eastern stock and bond markets also steadied after a jittery few days caused by a purge of royals and top officials by Saudi Arabia's Crown Prince.
"The stock market has run out of a little momentum since the blow-out on the (Japanese) topix so it feels like it's temporarily paused," said Societe Generale strategist Kit Juckes.
"We are waiting for some news from the Republicans on the (U.S.) tax plans, there is a bond market that has stalled and we've got rather soggy-looking emerging markets... We probably need to get U.S. Treasury yields higher to get things going again."
MSCI's all-country equity index is clocking year-to-date gains of almost 19 percent. http://reut.rs/1WAiOSC
But as a measure of relative calm of the current bull market and a reflection of the low volatility environment that has dominated all year, none of the most recent 10 daily gains have exceeded half a percent and more than half of them were less than 0.1 percent.
Among currencies, the New Zealand dollar was the day's big mover, surging about 1 percent to a two-week high of $0.6974 before dipping to trade at $0.6956.
The kiwi soared after the Reserve Bank of New Zealand (RBNZ) said the country's fiscal stimulus and the currency's recent fall following messy elections would lead to faster inflation and probably an earlier rise in interest rates.
On Thursday, the central bank held rates steady at 1.75 percent, as widely expected.
The dollar index against a basket of six major currencies was 0.3 percent lower at 94.568 as it drifted further from the three-month high of 95.150 set in late October.
A U.S. Senate tax-cut bill, differing from one already in the House of Representatives, was expected to be unveiled on Thursday, complicating a Republican tax overhaul push and increasing scepticism on Wall Street about the effort.
"There's very much a risk of disappointment. The U.S. dollar could go through a weakening phase on the back of uncertainty around that tax reform," said Steven Dooley, currency strategist for Western Union Business Solutions in Melbourne.
Some also focused on fallout from Democrat wins in regional U.S. elections this week as a signal for next years mid-term Congressional elections for President Donald Trump.
Trump himself was in China on Thursday, pressing President Xi Jinping to do more to rein in North Korea and to open the Chinese economy -- the second biggest in the world after the United States -- to more foreign firms.
The euro was shifting course, jetting back up towards $1.1650 as one of the European Central Bank's most influential policymakers acknowledged the bank's stimulus wouldn't last forever.
"Personally, I don't think quantitative easing can be a permanent instrument of ECB monetary policy simply because financial markets are not deep enough," Benoit Coeure said.
In commodity markets, Brent and U.S. crude oil futures were little changed at $63.50 and $56.90 a barrel respectively, having hit two-year highs earlier in the week following a 40 percent surge since July.
U.S. data showing a rise in domestic crude production had weighed on sentiment overnight but the Middle East uncertainty in Saudi Arabia limited the losses.
Gold added 0.2 percent to $1,283.45 an ounce after rising to a three-week high of $1,287.13 an ounce the previous day.
Palladium hovered near a 16-year high of $1,019 while nickel fell by more than 2 percent in London to its weakest since October as hype over potential electric vehicle demand that has been driving it higher eased.
The nickel market had been ignoring downside risks from policy developments in supply markets Indonesia and the Philippines, and instead focusing on potential future demand from electric vehicle batteries, said Morgan Stanley in a report.
"We (have) heard little to alter our view that producing NiSO (nickel sulphate) isn't particularly challenging/costly and we see near-term downside risk to price," it said.
Cryptocurrency Bitcoin skidded back almost 5 percent.
It had hit a record high just shy of $8,000 on Wednesday after a coalition of developers and investors suspended a software upgrade planned for next Thursday that could have split the digital currency in two. (Additional reporting by Shinichi Saoshiro; editing by Gareth Jones)