Portuguese Prime Minister Francisco Pinto Balsemao said yesterday that his government considers the withdrawal of Cuban troops from the former Portuguese colony of Angola something to be decided "by the Angolan government by its own free decision."

In remarks at a luncheon at the National Press Club, Pinto Balsemao said he did not "consider myself in a position to advise the government of the United States--at least publicly." But informed Portuguese sources said that both Angola and the independence of neighboring South African-occupied Namibia had been discussed in meetings Wednesday between the visiting Portuguese prime minister and President Reagan.

The Reagan administration has sought to link independence of Namibia to the withdrawal of Cuban troops, estimated by the United States at 20,000 to 25,000, from Angola. Although this position is strongly supported by South Africa, other countries, including Portugal, have maintained that Angola has the sovereign right to ask the Cubans to stay, and that linking this issue with Namibia will only slow down progress toward independence.

Portugal has maintained close ties with Angola, as well as Mozambique, since both were granted independence following the 1974 Portuguese revolution. The Portuguese government on occasion has served as a neutral party in negotiations involving the two African nations. In an interview last month, Portuguese President Antonio Ramalho Eanes called for U.S. diplomatic recognition of Angola as a way of easing tensions and aiding eventual Cuban withdrawal.

On another subject, Pinto Balsemao said that Portugal looks favorably on a Lebanese request to send troops to the multinational peace-keeping force in that nation. He said his government considered the request, which also has been made to Brazil and Colombia, "positive" as a "matter of prestige for Portugal and the armed forces."