The dollar pinned near a six-week low today while  commodity currencies loitered around multi-year highs, as investors' focus shifted to how U.S. Federal Reserve chief  Jerome Powell might respond to resurgent inflation expectations.

The gains have come with a worldwide rise in inflation expectations and a big sell-off in longer-dated bonds.

Traders expect Powell, who testifies before Congress at 2030 IST, to provide some reassurance that the Fed will tolerate higher inflation without immediately hiking rates, which they said could calm bond markets and eventually weigh on the dollar.

Morning moves were slight ahead of his appearance, but renewed confidence that low U.S. interest rates will not lift anytime soon can likely clear the way for further gains in trade-exposed currencies at the dollar's expense.

The U.S. dollar index sat at 90.019 today, just above its lowest since mid-January.