Malaysia's state oil company Petronas [PETR.UL] sold last week a December-loading Miri Light cargo at a premium of about $4.50 a barrel to dated Brent, equivalent to about $69 at the latest prices, according to multiple traders that participate in the Asian regional crude market.

Australian Barrow Island and Cooper Basin crudes are now close to $70 a barrel currently, based on premiums for grades of about $1.50 a barrel to Malaysian benchmark grade Kimanis, said the traders. Kimanis itself is priced at a premium of about $4.40 a barrel to dated Brent, which was assessed at $64.07 a barrel on Monday by price reporting agency S&P Global Platts.

"Prices of domestic Australian grades are even higher than MCO (Malaysian Crude Oil)," an Asian trader said. "That would make them the most expensive crudes in the world."

Demand for these grades is rising because of the short distances to Asian refineries, which prize the crude for their low sulphur content and higher yields of more valuable oil products such as diesel, the traders said.

Some Asian oil traders already selling near $70/barrel thanks to premium grades - http://reut.rs/2zkEY9f

Demand for short-haul grades has increased after the Brent oil market structure flipped into backwardation, when prompt prices are more than later prices. That means the value of the crude drops over the course of the voyage.

The refiners are willing to pay up for the Australian and Malaysian crudes rather than incur the additional time and cost of shipping Brent supplies from the North Sea, the traders said. Typically, Asia-Pacific grades are sold to refineries in Southeast Asia and Australia or New Zealand that have a preference for low-sulphur oil.

Values for these grades have risen because of their scarcity. Petronas and its partners Royal Dutch Shell , ConocoPhillips (>> ConocoPhillips), Murphy Oil Corp (>> Murphy Oil Corporation), Pertamina [PERTM.UL] sell about 6 million barrels of Kimanis each month.

But volumes for other Malaysian grades such as Kikeh and Labuan have fallen as output declines at the mature fields.

Australia's crude and condensate production has been below 300,000 barrels per day (bpd) since September 2016, data from the country's Department of the Environment and Energy showed. In August it was 279,000 bpd.

Santos Ltd (>> Santos Ltd) produces about 30,000 bpd of Cooper Basin crude in southern Australia, according to its website.

Santos and its partners, Chevron Corp (>> Chevron Corporation) and Mobil Australia Resources Co, a unit of Exxon Mobil Corp (>> Exxon Mobil Corporation), produces 5,000 bpd of Barrow Island in western Australia, according to Santos.

(Reporting by Florence Tan; Editing by Gavin Maguire and Christian Schmollinger)

By Florence Tan