The House approved an emergency 45-day extension of the "Superfund" toxic-waste cleanup program yesterday because legislation reauthorizing a larger effort for another five years has been tied up in various committees.

The extension, approved by voice vote, was pushed through because authority for the tax that pays for the Superfund program expired Monday when the 1985 federal fiscal year ended.

Without new funds, the toxic cleanups would eventually come to a halt.

The extension must now go to the Senate for approval.

A new five-year Superfund program is proceeding through five House committees, but turf fights and other disputes have slowed it. Supporters said it could take another month before the full House is able to vote on the bill.

The Senate has approved a $7.6 billion Superfund program for the next five fiscal years. President Reagan proposed a $5.3 billion reauthorization. White House officials have raised the threat of a veto.

The expiring Superfund was authorized for five years in fiscal year 1980 at $1.6 billion.

In the House, only the Energy and Commerce Committee has moved on the legislation. It approved a $10.2 billion program in July that produced strong disagreement among Democrats on the panel and was denounced as too weak by environmentalists.

Four other committees have jurisdiction over parts of the program and until all act, the House cannot vote on a bill.

Rep. James J. Florio (D-N.J.), chief architect of the original Superfund legislation, said yesterday the 45-day extension was necessary to prevent the Environmental Protection Agency from further slowdowns in cleanup projects.

Florio said EPA has only about $125 million left in the expiring Superfund program. CAPTION: Picture, Rep. James J. Florio . . . $125 million is left in fund