BOSTON--With the state facing a projected deficit of $100 million, the House of Representatives gave initial approval yesterday--by a voice vote--to $338 million in additional spending for the current fiscal year.

Fiscal conservatives lashed out at the proponents of the spending plan, accusing them of worsening the state's fiscal crisis and paving the way for a massive, long-term tax hike.

"This proposal is outrageous," said Rep. Robert H. Marsh (R-Wellesley)."We can't even be sure how much [of] a deficit we have now, so the Ways and Means Committee comes to us with a request for additional spending. Where do they think this money is going to come from? This is outrageous."

Last Thursday, the Ways and Means Committee approved the supplemental budget--used to pay for unanticipated costs--and recommended that the full House pass it.

Most of the spending in the supplemental budget will fund human service programs, including many entitlements programs that the state is legally required to finance.

Among the items approved were: $192 million in Medicaid reimbursements, $18.8 million for the Aid to Families with Dependent Children program, $14.3 million for welfare relief funds and $12.3 million for Department of Social Services programs for children.

The supplemental appropriation does not include $37.3 million for interest payments on loans, and the legislature may therefore need to draw up a second supplemental budget to cover these costs.

Yesterday's debate once again raised questions of how the state will deal with this year's budget deficit, which Gov. Michael S. Dukakis' administration last week projected would be at least $100 million by June 30, the end of the fiscal year.

The administration continues to maintain that the solution is Dukakis' proposed $604 million tax hike on capital gains, gasoline, cigarettes, alcohol and long-distance telephone calls. Legislative leaders have said the Dukakis tax package is not being seriously considered.

Chair of the House Ways and Means Committee Richard A. Voke (D-Chelsea), who has flatly rejected the Dukakis proposal, was quick to deny the Republican charge yesterday that his committee's spending proposals were setting the stage for a long-term tax hike.

The House budget leader has said that this year's fiscal woes are the result of overspending and are not due to a revenue problem, as the governor maintains. He has said that possible solutions to this year's budget crunch include short-term borrowing, a one-time tax increase or unanticipated revenue growth in the final months of the fiscal year.

If the legislature accepts that premise, Voke said yesterday, the fiscal woes could be treated as a one-time problem. The "spigot of spending" was turned down in the $12.3 billion budget which the House approved last month, Voke said.

"The question of revenue will now be decided by the Senate. If they choose to link fiscal '89 with fiscal '90, they will lay the groundwork for a substantial tax increase," Voke said yesterday during debate.

The Senate Ways and Means Committee will open public hearings on the "no new taxes" House budget this morning. Although the spending plan has come under fire from human service advocates and municipal leaders for underfunding programs, Senate Ways and Means Chair Patricia McGovern (D-Lawrence) has said that the upper chamber is constitutionally unable to raise taxes.

Final House debate on the supplemental budget is expected to begin later this week.