WASHINGTON (AP) _ The Energy Department today pushed back the deadline for states to submit proposals for the $4.4 billion ''super collider'' from Aug. 3 to Sept. 2.

The department said it acted to give states time to revise their proposals in light of a congressional ban on consideration of direct financial incentives for the eagerly sought scientific installation.

A supplemental appropriations bill for the current fiscal year signed last week bars the department from considering offers of help from the states.

In today's letter to the states, the department said a state could still offer financial aid - in a sealed envelope that would not be opened unless its proposal is selected.

The ban on financial aid, imposed by senators from small states who feared they had no chance if rich states could ''buy'' the project, does not apply to site improvements such as roads, sewer lines and so forth. In addition, the department is still counting on receiving the land needed as a gift.

The super collider, if built, will smash beams of protons into each other at 20 times the energy possible today. It will have 3,000 scientific jobs, little pollution and an annual operating budget of $270 million.

The department said it still hoped to pick the site in July 1988 and confirm that decision in January 1989.