The dollar fell to fresh one-week lows against the other major currencies on Tuesday, as investors remained cautious ahead of testimony by Federal Reserve Chair Janet Yellen due to begin later in the day.
GBP/USD climbed 0.48% to a seven-week high of 1.4761.
The pound strengthened after two opinion polls released on Monday indicated that support for the 'Remain' campaign had regained its lead over a vote to exit the 28-member bloc.
An ORB poll for the Daily Telegraph newspaper showed that 53% of voters supported the Remain campaign, compared with 46% support for the Leave campaign.
A poll published by NatCen also showed Remain on 53% and Leave at 47%.
But a poll by YouGov for The Times newspaper showed Leave ahead on 44%, with Remain on 42%.
The poll was conducted over the weekend, after the killing of Jo Cox, a Labour Party member and supporter of EU membership.
EUR/USD added 0.18% to 1.1335.
The dollar was higher against the yen, with USD/JPY up 0.39% at 104.37 and was lower against the Swiss franc, with USD/CHF shedding 0.25% to 0.9592.
Earlier Tuesday, Japan’s Finance Minister Taro Aso said Tuesday that officials would not intervene in the currency market lightly.
The comments came amid concerns over recent strong gains in the safe haven yen, which tends to be bought by investors in times of heightened market uncertainty.
The Australian and New Zealand dollars were stronger, with AUD/USD up 0.56% at 0.7500 and with NZD/USD climbing 0.45% to 0.7151.
In the minutes of its June policy meeting released on Tuesday, the Reserve Bank of Australia remained positive about growth and employment in Australia, but still underlined the risks of low inflation.
The central bank gave no indication of potential rate cuts in the near future, easing investors’ concerns that the RBA could lower rates in the next 12 months.
Elsewhere, USD/CAD fell 0.27% to trade at 1.2769, the lowest since June 13.
The U.S. dollar index, which measures the greenback’s strength against a trade-weighted basket of six major currencies, was down 0.17% at 93.52, the lowest level since June 9.