Olam International has posted a fall in its full-year profit despite higher sales, as higher tax charges and a challenging business environment affected some segments of the company.

The commodities player said profit for the 12 months ended June 30 slipped 2.2 per cent to $362.6 million.

Revenue rose 21.7 per cent to $20.8 billion, as sales volume rose 49.5 per cent.

"Our headline results were dampened somewhat by the impact of increased tax charges versus last year and challenging market conditions which emerged in the fourth quarter and affected some parts of our business," said chief executive Sunny Verghese.

There was a one-off tax charge of $12.8 million resulting from the sale of a rice mill in India and the sale-and-leaseback of almond orchards in the United States.

"Despite this, underlying performance in most segments was robust overall, reflecting the strength of our business model and diversification in the sources of earnings across our platforms and geographies."

For the fourth quarter, Olam's profit was 48.1 per cent lower than in the same period a year ago, at $56.8 million.

This reflects higher tax charges of $50.6 million recognised during the quarter, compared with a net tax credit of $8.2 million in the same quarter a year ago.

Revenue for the three months rose 26 per cent to $6.5 billion.

Net asset value stood at $1.51 per share at the end of June, up from $1.39 a year ago.

Earnings per share for the full year was 14.36 cents, down from 14.96 cents the year before.