President Reagan was briefed yesterday on the tax proposal developed by Senate Finance Committee Chairman Bob Packwood (R-Ore.). Sources said the package included one of Reagan's cherished goals, the expansion of individual retirement accounts for nonworking spouses.

Today, Packwood is to begin explaining his plan in meetings with other Finance Committee members in hopes they will endorse using it as a starting point in drafting a tax-overhaul bill. Treasury Department officials, who were shown the plan last week, have not reacted publicly to the proposals. But sources speculated the meetings with other senators indicate the administration does not have major problems with the plan.

Reagan's own tax proposal would have authorized the creation of tax-deferred IRAs for non-working spouses, into which up to $2,000 could be contributed every year. Currently, workers can put $2,000 into an IRA and nonworking spouses can contribute $250 and delay payment of taxes on principal and interest until the money is withdrawn.

The House rejected Reagan's proposal, which the president has supported as a "pro-family" change in the tax code. Packwood is not likely to propose the full expansion to $2,000 but wants to liberalize spousal IRAs as much as revenue will permit.

Packwood's plan, which is subject to revision, also is believed to retain in full the deduction for charitable contributions, both for taxpayers who itemize their deductions and those who use the standard deduction. And, as Packwood has said in the past, the proposal would curtail the tax-deferred status of so-called 401(k) retirement savings plans, but not by as much as the House measure. The House bill would make it harder for taxpayers to have both an IRA and a 401(k).

Meanwhile, House Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) yesterday said he was willing to postpone the effective dates of certain provisions of the House-passed tax-overhaul bill that have drastically restricted issuance of tax-exempt bonds to finance state and local government operations. Because the House legislation is written to go into effect on Jan. 1 of this year, new bond issues have virtually come to a standstill.

Rostenkowski was referring to provisions affecting traditional governmental bonds, but Senate tax writers also are under pressure to retain the tax-exempt status of many quasi-governmental bonds that now pay for such projects as pollution control, airport facilities, hospitals and downtown development. The interest paid by these bonds is tax-free, which means issuers can offer a lower rate than private bonds.

Sen. David Durenberger (R-Minn.) said yesterday he hopes the Packwood measure adopts some of his proposals for ending abuses of tax-exempt bonds but retaining them for financing essential functions. The House measure would sharply limit the number of tax-exempt bonds that could be issued, while Durenberger's proposal has relatively weak limitations, but would narrow the types of uses for which tax-exempt bonds can be issued.