Police are seeking the public's help - as they reveal it's believed the woman fatally stabbed on an Auckland bus may have known the man charged with her murder

Officers are piecing together Bernice Marychurch's movements before her death in Onehunga last Wednesday.

Kael Leona has been charged with her murder.

Acting Detective Inspector Alisse Robertson says CCTV footage shows the pair together at several points throughout the day.

They want to hear from anyone who saw Marychurch with a man wearing a baseball cap with Niue written on it, a zip up camo-coloured hooded sweatshirt, light coloured pants and white shoes, carrying a black backpack.

Police also want to speak with anyone who was at Woolworths Onehunga and several bus stops, at certain times on Wednesday.