SINGAPORE Oil prices were flat in Asia on Tuesday as the market drifted sideways ahead next week's OPEC meeting and the renewal of Iraq's oil-for-food program.

By 0724 GMT, the U.S. light crude last stood at $28.43 per barrel, up five cents from Friday's New York settlement.

The market fell three cents to settle at $28.38 on Friday.

New York trading floors were closed on Monday for memorial day, while London was shut for a bank holiday.

Traders expected next week's Organization of Petroleum Exporting Countries ministerial meeting to leave the group's output unchanged.

Nigeria's top oil official was the latest OPEC member to indicate the group saw no need yet to alter its ceiling, already lifted twice this year to curb runaway prices.

"There is no reason to change the level of production, since the price is reasonable and demand is healthy and encouraging," presidential adviser on petroleum and energy Rilwanu Lukman told the OPEC News Agency.

Lukman, a former OPEC secretary general, will lead Nigeria's delegation to the June 5 OPEC meeting in Vienna, according to Reuters.

His view echoes those of several other oil ministers in the group who see oil prices stable and in no need of the dampener of higher output before higher seasonal demand kicks in later in the year.

Venezuelan Energy and Mines Minister Alvaro Silva said on Monday he saw OPEC's oil basket price oscillating in the $25 to $30 a barrel range, well above the cartel's official $22 to $28 target.

"We think that $25 should be a floor for OPEC. We have seen it move between $25 and $28 without any problem for the world economy," Silva said in a television interview on Monday.

A sustained 20-working day period over $28 will trigger an automatic release of 500,000 barrels per day extra production under the terms of OPEC's price band mechanism.

The price of OPEC's basket of crudes stood at $26.12 a barrel on Friday, the latest figure available.

But adding uncertainty to the market was the June 3 expiry of the current six month phase of Iraq's oil-for-food export program under the auspices of the United Nations.

Iraq wants a simple renewal of the current program. Britain and the United States seek to ease restrictions on civilian goods going to Iraq but also crackdown on oil smuggling.

Baghdad has threatened to halt oil exports if the UN Security Council adopts the so-called "smart sanctions" proposal.

Saudi Arabia, the world's largest oil producer, has said that it and other OPEC members would step in and fill any serious supply gaps created by a break in Iraqi exports, which average about 2.1 million barrels per day.