GLOBAL MARKETS-New York order spooks Wall Street, offsets calm from policy efforts

(Adds open of U.S. markets)

* Graphic: World FX rates in 2020 http://tmsnrt.rs/2egbfVh

* Wall Street retreats after New York issues stay at home order

* Dollar eases as central banks pledge liquidity

* Stocks gain after volatile week

* Oil set for steepest weekly fall since 1991

By Herbert Lash

NEW YORK, March 20 (Reuters) - Wall Street see-sawed on Friday after New York's governor ordered residents to stay at home, rattling investors who had taken comfort from fiscal and monetary stimulus measures to counter the coronavirus shock and ease unusually volatile markets.

A wave of policy efforts had halted a global scramble for cash that sharply boosted the dollar this week and had helped staunch the steep nosedive in global equity markets. Stocks had gained on Thursday in less-tumultuous trade.

But New York state Governor Andrew Cuomo said he would issue an executive order to mandate that 100% of the non-essential workforce stay home and all non-essential businesses close.

"It's spooked people, it spooked the market," said Tim Ghriskey, chief investment strategist at Inverness Counsel in New York. "It's all fear, fear of more negative headlines."

On Wall Street, the Dow Jones Industrial Average fell 31.52 points, or 0.16%, to 20,055.67. The S&P 500 lost 11.84 points, or 0.49%, to 2,397.55 and the Nasdaq Composite added 25.63 points, or 0.36%, to 7,176.21.

Gold rose more than 3% as it regained a bit of its safe-haven luster and the yield on U.S. Treasuries fell as emergency measures aimed at stabilizing financial markets took hold after days of sharp volatility.

Stocks in Europe notched their first two-day gain since U.S. and other equity markets tumbled from all-time or near-record highs in February to their sharpest decline in three decades.

In yet another response to tight markets, six major central banks announced a coordinated action to enhance liquidity in the dollar by increasing the frequency of their currency swap operations.

Markets have been reassured by the speedy central bank action this week but the full fiscal response from governments remains to be seen and is critical, said Kristina Hooper, chief global market strategist at Invesco in New York.

"The dash to cash we saw earlier this week has been relaxed a bit. Now Treasuries are once again perceived to be a safe-haven asset class," Hooper said. "That's good as it suggests at least a dialing down of risk-off sentiment."

Norway's central bank became the latest to cut interest rates, while China was set to unleash trillions of yuan of fiscal stimulus to revive its economy.

The dollar eased after currencies, from the Australian dollar to the British pound, tumbled to multi-year lows earlier this week.

MSCI's U.S.-centric gauge of stocks across the globe gained 0.62%, while emerging market stocks rose 5.27%.

The dollar is up about 3.5% against a basket of currencies through a week when investors liquidated everything from stocks to bonds to gold and commodities to raise cash. The dollar hit a three-year peak of 102.99 in early Asian trading.

The dollar index fell 0.33%, with the euro down 0.33% to $1.0655.

The Japanese yen weakened 0.71% versus the greenback at 111.52 per dollar.

U.S. home sales surged to a 13-year high in February, but the housing market recovery is likely to be derailed by the coronavirus outbreak, which has unleashed a wave of layoffs and left the American economy headed toward recession.

The global economy already is in recession as the hit to economic activity from the pandemic has become more widespread, according to economists polled by Reuters.

Oxford Economics cut its global growth forecast for 2020 to zero, making this year the second-weakest for the world economy in almost 50 years of comparable data, with only 2009, in the depths of the global financial crisis, being worse.

European shares jumped as a wave of fiscal and monetary stimulus tempted investors back into equity markets. The broad pan-European STOXX 600 index rose 1.44%.

Britain's FTSE rose 1%, Germany's DAX gained 4%, and France's CAC 40 rose 5.1%.

The European Central Bank's 750 million-euro emergency bond purchase scheme, announced on Wednesday, has boosted southern European debt, alleviating some concern over how already heavily indebted states would finance the fiscal measures needed to defend against coronavirus.

Investors in Asia were happy that Wall Street had not plunged again. South Korean shares bounced 7.4%, though that still left them down more than 11% for the week.

Australia's beleaguered market eked out a 0.70% gain, and futures for Japan's Nikkei were trading up at 17,710, compared with the cash close of 16,552.

Oil prices fell for the fourth week in a row, with U.S. crude on track for its worst week since 1991, as the coronavirus outbreak knocked the demand outlook and Moscow rejected U.S. intervention in its price war with Saudi Arabia.\

West Texas Intermediate fell $2.83 to $22.39 a barrel while Brent crude futures were down $1.24 to $27.23 a barrel.

Euro zone bond yields tumbled on Friday as risk sentiment picked up to support Southern European bonds,

Benchmark 10-year U.S. Treasury notes last rose 56/32 in price to yield 0.9464%. (Reporting by Herbert Lash; Editing by Dan Grebler)