Man allegedly stabbed by girlfriend's mum

A man has been stabbed by his girlfriend's mother after she walked into his bedroom in Sydney's east, police say.

The 58-year-old woman allegedly attacked the 34-year-old man at his Maroubra home at about 3.30pm on Saturday, stabbing him with a knife before he was able to disarm her.

Police were called and arrested the woman and a 68-year-old man.

The injured man was taken to Prince of Wales Hospital and treated for stab wounds to his right arm and shoulder.

The woman has been charged with wounding with intent to cause grievous bodily harm.

She was granted conditional bail to appear in Waverley Local Court on September 25.

The 65-year-old man was released without charge.