The monthly update shows inflation is worsening in Iran, despite growing political pressure on the government to halt the steep increase in prices.

The annual inflation rate by 21 July was 26.1 per cent. In June and May, inflation was 25 per cent and 24 per cent respectively.

The Central Bank of Iran's inflation figures only apply to urban areas, where more than 66 per cent of the population is understood to live.

Food prices have been worst hit by inflation with the cost of meat, beans and rice doubling over the last year.