The dollar has gained this week as Treasuries yields rose in more volatile trading as investors adjust to the possibility that the Federal Reserve will adopt a more hawkish tone and indicate that it may act sooner to raise interest rates.
Recent comments by Fed policymakers including Chair Janet Yellen have indicated that rate increases will be data dependent, and some fear that further declines in unemployment may pressure the U.S. central bank to tighten sooner.
U.S. dollar strength has also been aided by a worsening picture in Europe and Japan. The euro fell to 14-month lows against the greenback after the European Central Bank cut rates to new lows and launched an asset purchase program to ward off deflation.
The Bank of Japan is also expected to launch new stimulus to address low inflation and a flagging economy.
The dollar was last at 106.83 yen after earlier rising above 107 for the first time since September 2008. The euro rose to $1.294, up from a 14-month low of $1.2858 on Tuesday.
The dollar index fell 0.14 percent to 84.166, but was still on track for a ninth consecutive week of gains - its longest winning streak since 1997.
Sterling got some respite from a poll that helped calm nerves over Scotland's vote on independence in a week's time.
A poll late on Wednesday showed 53 percent of Scots intended to vote against a split from the UK, in contrast to a YouGov poll over the weekend showing 51 percent in favor.
Sterling rose 0.18 percent to $1.6242 after gaining 0.7 percent on Wednesday after the latest poll was published.
The dollar hit a seven-month peak against its New Zealand counterpart, which slid after the country's central bank said the kiwi's current level was ``unjustified and unsustainable''.
The kiwi sank as low as $0.8162, before recovering back to $0.8196.
More on foreign exchange.