US consumer prices rose last month and the underlying trend continued to strengthen, pointing to a steady increase in inflation pressures that keeps the Federal Reserve on track to gradually raise interest rates.

The Labour Department yesterday said its consumer price index (CPI) advanced 0.2 per cent, with the bulk due to a rise in the cost of accommodation.

The CPI rose 0.1 per cent in June.

In the 12 months through July, the CPI climbed 2.9 per cent, matching the increase in June.

Excluding the volatile food and energy components, the CPI rose 0.2 per cent, the same gain as in May and June. The annual increase in the so-called core CPI was 2.4 per cent, the largest rise since September 2008, from 2.3 per cent in June.

Economists polled by Reuters had forecast both the CPI and core CPI rising 0.2 per cent in July.

The Fed more closely tracks a different inflation measure, the personal consumption expenditures index excluding food and energy, which rose 1.9 per cent in June.

That gauge hit the US central bank's 2 per cent target in March for the first time in more than six years. Fed policymakers have said they will not be unduly concerned if it overshoots its target in the coming months.

The Fed has raised rates twice this year, in March and June, and investors overwhelmingly expect a hike at the upcoming policy meeting next month.

The Fed currently forecasts a total of four rate hikes this year, with investors expecting a final 2018 nudge upwards in the benchmark overnight lending rate in December.

Inflation pressures are seen continuing to build amid low unemployment and increasing difficulty reported by employers in filling positions. Rising raw material costs are also expected to push up inflation as manufacturers pay more, in part because of tariffs imposed by the Trump administration on lumber, aluminium and steel imports.

Last month, petrol prices fell 0.6 per cent after increasing 0.5 per cent in June. Food prices edged up 0.1 per cent last month after rising 0.2 per cent in June.

Owners' equivalent rent of primary residence, which is what a homeowner would pay to rent or receive from renting a home, advanced 0.3 per cent last month after increasing by the same margin in June. Overall, the so-called shelter index has risen 3.5 per cent over the last year.

REUTERS