Singapore, June 26 (Reuters) - A Reuters poll showed that Saudi Arabia may cut its official selling price for Arab Light crude to Asian buyers sharply in August to a four-month low, following a decline in spot crude prices due to increased supplies from the Middle East.

Four industry sources surveyed by Reuters said the official selling price for Arab Light crude could fall to a premium of between $1.50 and $3 per barrel above the average of Dubai and Oman crudes, roughly $6.50 to $8 per barrel lower than the July price.

Survey participants expect official selling prices for the rest of Saudi crude to fall by the same amount.

These anticipated reductions come after a sharp decline in Middle Eastern spot crude markets. Dubai crude's cash premiums over swap contracts turned into a discount of $1.64 per barrel this week, the lowest level in six years.

Dubai's cash premiums have averaged $3.06 per barrel so far this month, down from $9.59 per barrel in May. Spot spreads for Oman crude also fell to their lowest level in six years this week.

This market decline came as more oil shipments crossed the Strait of Hormuz following the ceasefire, reducing concerns about supply disruptions.

Other producers, including the UAE, Iraq, and Qatar, offered oil shipments on the spot market. Pressure also increased due to expectations of increased Iranian exports following its receipt of a temporary waiver from US sanctions.

High prices for Saudi crude have already affected demand from China, with buyers significantly reducing shipment volumes in July, after also cutting shipments in June.

Shipping data showed that Saudi Aramco resumed loading oil at Ras Tanura port on Friday after a nearly four-month hiatus, signaling further recovery in export flows from the Gulf region.

The state-owned oil company had diverted crude exports to the Yanbu terminal on the Red Sea, after the conflict disrupted shipping through the Strait of Hormuz.

Official selling prices for Saudi crude are usually announced around the fifth day of each month, and they set the direction for Iranian, Kuwaiti and Iraqi oil prices, affecting about nine million barrels per day of crude destined for Asia.

Saudi Aramco sets its crude oil prices based on customer recommendations and calculations of the change in the value of oil during the past month, using product returns and prices.

Saudi Aramco officials do not comment on the kingdom's official monthly selling prices.