ERBIL, Iraq, May 2 — Kurdish and Sunni Arab officials expressed deep reservations today about the draft version of a national oil law and related legislation, misgivings that could derail one of the benchmark measures of progress in Iraq laid down by President George W. Bush.

The draft law, which establishes a framework for the fair distribution of oil revenues, was approved by the Iraqi cabinet in late February after months of protracted negotiations. The White House was hoping for quick passage to lay the groundwork for a political settlement among the country’s ethnic and sectarian factions. But the new Kurdish concerns have created doubts about the bill even before Parliament is to pick it up for debate.

The issue comes at a sensitive moment for Mr. Bush, who today began negotiations with Congressional Democrats over a new war-spending measure. The president vetoed a $124 billion bill on Tuesday because it included timetables for troop withdrawals, and a House vote today fell short of the two-thirds majority needed to override the veto, with 222 voting in favor and 203 opposing the override.

In a speech to a construction industry trade group in Washington, Mr. Bush said he is “confident that with good will on both sides, that we can move beyond political statements” and agree on a new measure. But he continued to criticize Congress for trying to use the bill to dictate timelines for withdrawal.