PRETORIA (AFP) - Preparations have been made to allow Oscar Pistorius's murder trial to sit two weeks longer than planned, the prosecution said on Thursday, as the planned March 20 end date looks increasingly unrealistic.

Assistant prosecutor Andrea Johnson said they had been informed the court can sit until April 4, if the case has not concluded before then.

Around a dozen witnesses for the prosecution have so far been called, with the case coming to the end of its second of three weeks.

Still more state witnesses are expected to testify, before the defence gets to call its own witnesses - including star athlete Pistorius himself, who denies intentionally killing his girlfriend Reeva Steenkamp last year.

The two sides then have to wrap up their arguments.

Given the current pace of proceedings, that is unlikely to happen in the five days remaining.

If the trial continues beyond April 4 judge Thokozile Masipa will have to reconvene sometime after April 11 because of a scheduled holiday.

Even if the trial concludes by April 4, a ruling and any sentencing would likely come later.