Rep. Glenn English (D-Okla.) said yesterday he will hold hearings on a proposed executive order for government secrecy classifications in light of White House assurances that there is no great rush to issue it.

The draft, which would make it easier to classify government documents and keep them secret, was sent to selected congressional committees with a Feb. 22 deadline for comment.

English, chairman of the House government information subcommittee, and seven other House Democrats asked for more time in a Feb. 12 letter to President Reagan's new national security adviser, William P. Clark. English said Clark assured him Monday that no quick action was expected.

English said he regarded his hearings, set for March 10-11, as important because "There has been little public circulation of the draft order and little public debate."

Unlike earlier orders by Presidents Carter and Nixon, he noted, the Reagan draft apparently would make it easier to classify "ordinary information not readily classifiable now" and might also make new categories of scientific and technical information subject to classification for the first time.

There was still some confusion about deadlines, though. In a follow-up letter delivered to English yesterday, Clark asked him to submit comments to presidential counselor Edwin Meese III by March 5, before English's scheduled hearings.

English said he assumed there was some flexibility in the new deadline. An aide to Clark indicated that this was a safe assumption.