The threat of a major debate on abortion and a filibuster has delayed Senate action on the District's fiscal 1986 appropriations bill, according to knowledgeable Senate sources.

Sen. Gordon J. Humphrey (R-N.H.) has announced his intention to offer an amendment that would prohibit any of the funds in the bill, local as well as federal, from being used to pay for abortions except when the life of the mother is in danger.

A group of senators who advocate abortion rights, including Lowell P. Weicker Jr. (R-Conn.), Howard Metzenbaum (D-Ohio) and Bob Packwood (R-Ore.), plan to filibuster the bill if they lose on the abortion amendment, according to several staff aides.

The three "would be talking at length on the issue" if Humphrey won, a spokesman for Metzenbaum said.

"We are poised to oppose Humphrey," said a Weicker aide.

The House approved a strict antiabortion amendment in its version of the D.C. appropriations bill, prohibiting the use of any funds for abortion with no exceptions.

The legislation includes the District's budget for fiscal 1986, which begins today.

The measure was supposed to have been brought up on the Senate floor last week but was held up because of the abortion controversy. The measure may be considered this week, according to Senate aides. In the meantime, the city can operate under a catchall resolution approved by Congress to continue government spending until appropriations bills are approved.

For a number of years, the District's bill as well as other appropriations bills have included a prohibition of the use of federal funds for abortions. But if the House-passed amendment and Humphrey's proposal are successful, it would be the first time Congress prohibited a local government from using its own funds to pay for abortions for poor women.

When the appropriations bill was considered by the Senate Appropriations subcommittee on the District, Sen. Arlen Specter (R-Pa.), the subcommittee chairman, deleted the House antiabortion language and substituted the old restriction that applied to federal funds only.

If that approach is retained in the Senate's version of the bill, it would be relatively easy to get that provision included in the final version of the measure negotiated by House and Senate conferees.

Both Specter and his counterpart in the House, Julian C. Dixon (D-Calif.), who would be leading their respective conferees, oppose the House amendment.

Even if the Humphrey amendment is adopted, it is somewhat different from the House version and would be an item to be negotiated in conference, with plenty of room for the two chairmen to maneuver on the issue, according to knowledgeable officials.

For this reason, it is possible that an amendment may be offered by another antiabortion senator, possibly Jesse Helms (R-N.C.), to simply include the House language in the Senate version, which would theoretically mean it could not be changed in conference. An aide to Helms said she could not confirm whether Helms planned to offer such an amendment.

On another controversial issue, Sen. Mack Mattingly (R-Ga.) plans to offer an amendment to freeze the level of consultant contracts in the District, an aide to Mattingly confirmed.

The House this year included an amendment stating that all District contracts must be awarded competitively. The Senate subcommittee deleted that language from its version, so that the issue could be negotiated in conference.