TORONTO -- A new poll indicating that Britons will likely vote to stay in the European Union helped rally North American stock markets Monday, while the loonie rebounded sharply against the U.S. dollar for a second consecutive session.

The Canadian dollar climbed 0.42 of a U.S. cent to 78.07 cents US after having risen half a cent on Friday.

In Toronto, the country's main stock exchange, the S&P/TSX composite, shot up 113.37 points to 14,015.14, with energy and mining stocks leading the way.

The optimism carried over into New York where the Dow Jones industrial average soared 129.71 points to 17,804.87, while the broader S&P 500 composite index advanced 12.03 points to 2,083.25. The tech-heavy Nasdaq composite ran up 36.87 points to 4,837.21.

The latest opinion polls suggests that Britain is more likely to vote to remain in the EU than leave in Thursday's referendum. Uncertainty over the economic consequences of a vote to leave the EU, commonly referred to as Brexit, had cast a cloud over global markets in the last two weeks.

"This is more of a catch up to what we lost last week when the pessimism around the outcome really set in," said Craig Fehr, a Canadian market strategist at Edward Jones in St. Louis.

"I think the bigger conclusion here is that we are seeing global equity markets, trillions of dollars, tied to these small but certainly important swings in the polls. At the end of the day, it's going to be the vote that matters."

Fehr said the markets are so focused on the pending Brexit vote that any new data can fuel volatility.

"We will see the outcome of the Brexit vote and then the market will turn its sights to the next issue -- back to speculating on what the Fed will do (about interest rates)," he said.

Investors will also be watching to see what U.S. Federal Reserve chair Janet Yellen will say before the Senate Banking Committee on Tuesday. Most expect Yellen to echo Fed comments that the U.S. central bank will only raise interest rates if data shows the economy is strong enough to support such a move.

Rumours about the likelihood of a "stay" vote, along with a weakened U.S. dollar also helped commodities as the August crude contract climbed $1.40 to US$49.96 a barrel.

"The rise in oil is on the premise that if indeed the Brexit vote doesn't end with the U.K. leaving, that can provide a little more global economic stability... that suggests that there is more support for oil prices," said Fehr.

In other commodities, July natural gas jumped 12 cents to US$2.75 per mmBTU while July copper rose four cents to US$2.09 a pound.

Gold bullion, which is usually attractive to investors during downturns in equity markets, was lower, with the August gold contract falling $2.70 to US$1,292.10 a troy ounce.