WARSAW, Poland (AP) _ Deputy Secretary of State John C. Whitehead on Wednesday praised Poland's progress in human rights but said renewed U.S. economic aid depended on its implementation of economic reforms.

Whitehead, the State Department's No. 2 official, said he was ''impressed with the progress that has been made in all areas of human rights'' in Poland since his last visit in January 1987, but he said there still were some concerns, including ''a handful'' of political prisoners.

Opposition activists say there are about 20 political prisoners.

Whitehead said ''considerable progress'' had been made in improving U.S.-Polish relations but added that ''our capacity to move forward will continue to depend on our judgment concerning the situation and prospects for human rights and national reconciliation in Poland.''

He also met for 2 1/2 hours with Polish leader Gen. Wojciech Jaruzelski. Relations between the United States and Poland have been on the upswing since the United States lifted its last remaining economic sanctions against Poland a year ago. That restored Poland's most favored nation status and lifted a ban on new credits.

Asked about prospects of new U.S. economic credits to Poland this year, Whitehead said the United States wanted to help Poland's economic recovery but tht ''help can only be effective if the economic changes win the support of a broad spectrum of Polish society,'' including the Roman Catholic Church and the outlawed Solidarity trade union federation.

Whitehead's visit coincided with the imposition of the steepest price increases in Poland in six years. Food prices have been raised an average of 40 percent, and rents have gone up about 50 percent. The government said the increases were vital to an economic reform program unveiled last fall.

Solidarity has demanded that the price increases be withdrawn, saying they will only threaten living standards without improving the economy.

Whitehead's visit last year was the first by a high-ranking U.S. official since relations soured following Poland's imposition of martial law in December 1981. Martial law was lifted in July 1983.