FINNISH baritone Jorma Hynninen brings both heart and sisu (Finnish for inner strength) to a program of Sibelius and Wolf lieder in his long-awaited Washington debut Sunday afternoon at the Kennedy Center.

Though far from a household name in the United States, Hynninen is an acclaimed international artist with an enviable reputation as a recitalist and opera singer, having performed roles by Mozart to Wagner to fellow countryman Aulis Sallinen with the major companies worldwide.

No longer Finland's best-kept secret, he is now recognized as one of the preeminent vocalists of his generation. Blond, athletic and now in his mid-40s, Hynninen resembles a cross between Harrison Ford and William Hurt, yet keeps a moderate concert schedule that belies his demand. The jet-setter's life has little appeal for this star of the Met and the Finnish National Opera, where he also doubles as artistic director.

Recordings have brought increased exposure for Hynninen, who prefers singing lieder in an intimate setting to belting opera in the big halls. His CD collection of Jean Sibelius songs lifts relatively unfamiliar material to an exalted plane. While not in the same league as Schubert and Schumann as a composer of lieder, Sibelius nevertheless expresses himself with an honest, direct eloquence that emphasizes melodic content over literary references drawn from texts by the Finnish nature poets he favored. In these 25 selections (representing nearly one-quarter of Sibelius' song output), Hynninen is in top form, his voice an ideal mixture of beauty, warmth and drama. This splendid disc was recorded in 1980 at the Munkkivuori Church in Helsinki, a venue obviously congenial to Hynninen's rich lyric baritone.

JORMA HYNNINEN --

"Jean Sibelius: Lieder" (Finlandia FACD 202 S). Appearing Sunday at the Kennedy Center Concert Hall.