April 30 (Reuters) - Pekao, Poland's second-biggest lender, posted a 5% year-on-year rise in first-quarter net profit on Tuesday, driven by higher net interest income.

Profit was 1.51 billion zlotys ($374.73 million), above the 1.47 billion zlotys forecast by analysts in a company-compiled consensus.

Net interest income rose 11.3% to 3.09 billion zlotys.

Its net interest margin in the first quarter rose to 4.17% from 4.15% year ago, and 4.16% in the prior quarter.

New mortgage loans in the first quarter jumped six-fold to 4.3 billion zlotys. Pekao said that mortgage sales were largely driven by the 2% loan scheme introduced by the previous government.

($1 = 4.0296 zlotys) (Reporting by Adrianna Ebert; Editing by Savio D'Souza and Kim Coghill)