Taxes are seen playing a central role in the structure and size of any demerger should it go ahead.

BHP is on track to export well over 220 milliom tonnes of iron ore in the 2014 financial year. Photo: Reuters

BHP Billiton looks set to easily beat its iron ore export target for the 2014 financial year, after data published by its Port Hedland neighbours indirectly shed light on BHP's performance.

Australia's biggest company needed to export about 54 million tonnes of iron ore during the June quarter - including tonnes owned by joint venture partners - to meet its full-year target of exporting 217 million tonnes.

The miner appears to have easily achieved that, after Fortescue Metals Group and Atlas Iron illuminated Port Hedland data by both publishing their export numbers earlier than expected last week.

Just less than 105 million tonnes of iron ore were shipped through Port Hedland in the June quarter and, after subtracting the contributions of Fortescue and Atlas, BHP appears to have shipped just over 62 million tonnes.

Such a performance would put BHP on track to export well over 220 million tonnes in the 2014 financial year, smashing its guidance and proving that expansions to its Pilbara export system towards 220 million tonnes per year has arrived.

The vow to export 217 million tonnes in the financial year was itself an improvement, after BHP began the year promising to export 207 million tonnes.

Beating the full-year export target would be a boost for the miner, given iron ore remains its biggest money spinner.

But it would not be a surprise to analysts, many of whom have been tipping a guidance beat for months.

As far back as April, Macquarie analyst Adrian Wood was expecting BHP to exceed its iron ore export guidance by 3 million tonnes.

The increases have been achieved on the back of an efficiency campaign within the inner harbour of Port Hedland, and BHP iron ore boss Jimmy Wilson recently indicated that campaign would continue for some time yet.

''We haven't finished squeezing the lemon on the inner harbour,'' he told reporters last month.

Despite recent falls in the benchmark iron ore price - it was fetching $US96.9 per tonne over the weekend - ANZ analysts have predicted it could return above $US100 per tonne within a week.

Iron ore remains Australia's most lucrative export commodity, and the benchmark price has been below $US100 per tonne for more than eight weeks.

BHP declined to comment, and is expected to publish its June quarter production numbers on July 23. Rio Tinto is expected to publish its results on Wednesday.