Many officials at the US Federal Reserve's April policy meeting believed it would be premature to raise interest rates in June and that a bump in inflation was being offset by a weaker labour market and softer data, according to minutes from the meeting released this evening.

"Many participants, however, thought it unlikely that the data available in June would provide sufficient confirmation that the conditions for raising (interest rates) had been satisfied ...," the minutes said.

The minutes also showed most participants expected the US economy to pick up pace after a slowdown in the first quarter and that labour market conditions would improve.

But Fed officials also flagged a number of concerns weighing on the central bank, including disappointment that falling oil prices did not spur consumer spending as much as some of them had hoped. Economic worries in China and Greece were also cited.

The minutes largely reflected the Fed's April policy statement, which pointed to economic softness but described the slow growth as reflecting, in part, transitory factors.

Investors are awaiting a speech on Friday by Fed Chair Janet Yellen, with all eyes on whether she believes things remain on track, or nods to the latest batch of weak US economic data.

The minutes also mentioned concerns about bond market volatility and the possibility of long-term rates spiking when the Fed begins to raise rates - a worry Ms Yellen spoke of in public remarks earlier this month.