Fortescue Metals Group says it has had its highest level of quarterly shipments in the three months since June.

In an update on its September quarter operations, Fortescue said it shipped more than 12 million tonnes of iron ore in the period, in line with its guidance provided in the previous quarter.

The average selling price for the period would be approximately $160 per tonne, subject to final adjustments for shipments at the end of September, Fortescue said. The average iron ore sales price achieved by Fortescue in the year to June, including freight costs, was $US149 ($A152.92).

The company said it continued to sell all of its production, with no cancellations or deferral of cargoes.

Cash flow remained strong despite capital market volatility, with about $US2 billion of cash on hand, Fortescue said.

Expansion works were progressing on time and on budget, it said.

Fortescue shares were up 20 cents, or 4.5 per cent, to $4.65 at 1042 AEST.