SINGAPORE (Reuters) -Investors unnerved by the prospect of U.S. President Donald Trump's impending tariffs drove a wave of selling on Friday in risk-sensitive currencies such as the Aussie, sent bitcoin tumbling and gave safe-haven support to the dollar.

On Thursday Trump said his proposed tariffs of 25% on Mexican and Canadian goods would take effect on March 4 along with an extra 10% duty on Chinese imports, defying expectations of those who hoped for a further delay in the levies.

The risk-off moves gathered steam during the trading session, with cryptocurrencies among the biggest losers for the day as bitcoin slid more than 5% to bottom at $79,125.53, its weakest level since November 11.

Ether similarly tumbled more than 5% to an over 13-month low of $2,099.37.

The two tokens were on track for their steepest monthly falls since June 2022, following a towering rally late last year on optimism that the Trump administration would be a boon for the asset class.

"Bitcoin's fall below $80,000 shows that positive sentiments from a crypto-friendly administration and high-profile endorsements have run their course," said Joshua Chu, co-chair of the Hong Kong Web3 Association.

"It's clear bitcoin is a risk asset, not the inflation hedge or digital gold it's often touted to be."

In the broader market, the Aussie slid 0.4% to its lowest in more than three weeks at $0.62105, extending a decline of 1% from the previous session. It was on track for a weekly loss of nearly 2%.

The New Zealand dollar similarly fell more than 0.5% to $0.5599 and was set to shed 1.9% for the week.

The euro struggled at a two-week low of $1.0380 and was also headed for a weekly fall of 0.6%, which would put its monthly gain at just 0.35%.

"Markets were shaken out of tariff complacency," said Sim Moh Siong, currency strategist at Bank of Singapore.

"We continue to see scope for some U.S. dollar strength if tariff risks materialise by April even as our conviction that the U.S. dollar can strengthen meaningfully is now reduced given cracks in the U.S. exceptionalism story."

The Canadian dollar slipped to a more than three-week low of C$1.4452, as it heads for a weekly decline of 1.5%.

The greenback's moves against the Chinese yuan were more muted as it was little changed at 7.2846, after rising to a two-week top of 7.2914 earlier in the session.

"Ahead of China's most important political event next week, investors are likely staying clear of the yuan as (the People's Bank of China) would likely intervene to ensure the yuan's stability," said Alex Loo, FX and macro strategist at TD Securities.

Against a basket of currencies, the greenback struck a two-week top of 107.42, extending its 0.8% jump on Thursday.

Still, the index was on track for a monthly loss of more than 1%, its worst since August, as the dollar faces downward pressure amid worries over the health of the world's largest economy.

A raft of weaker-than-expected economic data has led traders to ramp up bets for more Federal Reserve rate cuts this year, in turn sending U.S. Treasury yields lower and proving a drag on the dollar.

"For now, it's the growth story that is dominating, pushing yields lower, while at the same time, we're starting to see a little bit of an increase in volatility in markets in general and that risk aversion as well," said Rodrigo Catril, senior currency strategist at National Australia Bank.

Elsewhere, sterling fell 0.17% to $1.2580, but was set to end the month with a gain of more than 1.6% for its best performance in five months.

The pound has partly been supported by expectations for relatively fewer rate cuts from the Bank of England than some other central banks, namely the European Central Bank.

The yen fell 0.1% to 149.91 per dollar .

Still, the Japanese currency was set to rise 3.5% for the month, its best since last July, on heightened bets of more rate hikes this year by the Bank of Japan (BOJ).

Core consumer prices in Tokyo slowed in February, but kept well above the BOJ's 2% target, data showed on Friday.