By voice vote and without a murmur of discussion, House members yesterday voted themselves an increase in income and a tax cut. The tax cut would go to senators as well.

The House first approved legislation to allow married members of Congress who have homes here and in their districts to take tax deductions for much of the cost of maintaining the homes here. For many this would mean a sizable tax cut.

Then by unanimous consent the House amended its rules to double from $9,099 to $18,198 the amount members may earn from speeches and other outside activities. When forced to record themselves on this measure earlier this year, House members defeated it 271 to 147.

Done in the waning hours and last-minute crush of the session, yesterday's two votes together amount to a back-door congressional pay raise, which the House has been unwilling to vote directly for fear of public criticism.

About an hour after the votes four members of the House, claiming that they had no idea of what had been taking place on the floor, complained bitterly about the furtiveness of the action on outside income.

"This is the pickpocket's way," Rep. Millicent Fenwick (R-N.J.) told colleagues. "It just causes this House to be looked upon with distrust by the people of this country," Rep. Sam B. Hall Jr. (D-Tex.) said.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) replied that the unanimous consent request had been cleared by the leadership of both parties before it was made by Rep. John P. Murtha (D-Pa.).

The entire consideration of the proposal took less than 20 seconds, and no explanation was given of the controversial action. The House and Senate had both set ceilings limiting outside earned income to 15 percent of their salaries as part of the general reform drive during the post-Watergate period and as part of an agreement tied to raising their salaries, which now stand at $60,662.50 annually.

Since then, the Senate has relaxed its restriction twice, first raising the ceiling to $25,000 and, earlier this year, eliminating it. The House until yesterday had taken no similar action.

The tax-deduction issue arose after Congress earlier this year eliminated a $3,000 ceiling on the business deductions House and Senate members can take for the costs of living in Washington.

The problem is that there are also limits in the tax code on deductions any taxpayers can take for second homes. These are designed to keep people from cutting their taxes with vacation homes. The limits apply especially to taxpayers with families.

Under these limits, many married members faced the prospect that the Internal Revenue Service would still disallow depreciation deductions on their Washington homes along with deductions for maintenance and utilities.

This is what the House moved to avoid yesterday. The Senate is expected to follow suit, perhaps today.