Five top Senate Republican leaders have given President Reagan new estimates of the massive budget deficits that may occur under the president's current economic plans, and advised him of the "political realities" to be faced if the deficits are not controlled, Sen. Robert J. Dole (R-Kan.) said yesterday.

On Friday, the president met for more than an hour with the Republican leaders, including the chairmen of the Senate's three economic committees -- Finance, Budget and Appropriations.

Dole, chairman of the Finance Committee, said that as those responsible for handling the president's proposals in the Senate, the group wanted to let him know "the political realities of what we can and cannot do, to give him a fair idea of what we think about the deficits."

Sen. Pete V. Domenici (R-N.M.), chairman of the Senate Budget Committee, gave the president new calculations of the deficits that may occur under Reagan's current spending and tax plans. The estimates included a deficit of some $82 billion in fiscal 1982, followed by $165 billion in 1983 and $215 billion in 1984.

The senators suggested several ways to counter those levels, including making larger cuts in the defense budget. They also suggested increasing taxes, and possibly cutting some entitlement programs, such as Medicare and Medicaid.

Dole said that the senators let the president know that the necessary budget cuts would be much harder to achieve next year than this past year if some of those alternatives were not considered. Dole also said that the president was reminded of the many Republicans in key committees coming up for election in 1982.

During the meeting, the president remained noncommital, but tended to stand by his refusal to offer new tax increases or larger cuts in the defense spending, Dole said.