The dollar was broadly weaker on Wednesday as risk appetite returned to markets, boosting higher-risk currencies, while sterling and the euro rose on the last day of campaigning before Britain's referendum on European Union membership.
The sterling hit its highest levels of the year after polls showed that 51 percent back remaining in the EU. The pound sterling was last at $1.4798, up 0.96 percent on the day.
A swing in bookmaker odds towards Britain choosing to remain in the EU, following the murder of a British lawmaker last week, helped boost currencies like the Australian and New Zealand dollars, considered riskier investments because of their ties to commodity prices.
The shift also helped sterling to recover 5 percent from lows around $1.40 last week.
"Part of it is gradually more and more the risk from Brexit being removed, something that started last week when we saw the polls changing around," said Charles St-Arnaud, senior strategist and economist at Nomura Securities International in London.