A woman in her 70s is in a critical situation after she has cycled in the south of Dublin.
The event took place around 7:45 pm in Village Bank on Monday when the woman departed from a bus.
It is thought she was trying to cross the road when the accident happened.
She was taken to an ambulance to St James's Hospital and has since been transferred to Beaumont. The guards said her situation was essential.
The motorcycle, one in his 30s, was taken to St Vincent's Hospital where he was treated for a small wound.
The scene has been reviewed by inspectors of the force's violent attack and investigations are continuing.
The police have made a claim for witnesses and anyone with information is asked to contact Garda Dundrum 01-6665600 or the Garda Secret Line 6 666 111.