"Of course this result is bad for the SDP and the Restart Coalition. I'm not running away from responsibility and I'm willing to step down. We'll discuss it tomorrow at the party Presidency," he told reporters in the SDP headquarters.
Restart has won 43 seats in parliament in Sunday's election, according to incomplete results, which is the SDP's poorest result in the past three parliamentary elections.
Bernardic congratulated the Croatian Democratic Union (HDZ) and its leader Andrej Plenkovic on the victory of the 10th parliamentary elections.