Pontiff plans to take part in Palm Sunday Mass, Vatican says.

Pope Francis is set to be discharged from hospital on Saturday, the Vatican has confirmed, after the 86-year-old pontiff was hospitalised on Wednesday with a respiratory infection.

The Vatican said in a statement on Friday that Francis is expected to return to his Santa Marta residence on Saturday "upon the outcome of the results of the last examinations this morning."

The pontiff is being treated with antiobiotics for viral bronchitis at Rome's Gemelli hospital after experiencing difficulty breathing earlier this week.

Vatican spokesman Matteo Bruni said that Francis plans to take part in the Palm Sunday Mass in St Peter’s Square on Sunday, at the beginning of the Holy Week schedule leading up to Easter.

The pope's recovery has been "normal", according to Bruni, who stated on Thursday that Francis had experienced a "marked improvement in his state of health" following treatment at the Gemelli.

Bruni also said that the pontiff had eaten pizza on Thursday evening with doctors, nurses and staff, and on Friday morning after breakfast the pope read some newspapers and resumed work.

Italian media reported on Thursday that Cardinal Leonardo Sandri was set to celebrate Palm Sunday Mass, with various other cardinals lined up to preside over Easter ceremonies.