Horror as five-year-old girl is attacked by a dog while in her mum's arms at Sydney Park, Alexandria

A mother has issued an urgent warning after an off-lead dog terrorised and bit her two young children at a popular park.

The shocked mum claimed the medium-sized brown pooch was apparently being exercised in the Sydney Park wetlands area in inner-city Alexandria at about 12.30pm on Monday when it broke from a group of canines being supervised by a dog walker.

'It initially bailed up my 10-year-old son against a tree and scratched him and then chased after my daughter,' the woman wrote on community Facebook page.

'The dog then knocked my daughter to the ground and then bit and scratched her, continuing to chase us and jumping up to bite her legs even when she was in my arms and I was trying to get away from it.'

The little girl's injuries are unknown. 

The woman described the female dog walker as wearing a yellow shirt and having dark hair who was supervising eight dogs at the time.

A mother claims a dog has attacked her two young children at a popular park in inner-city Sydney (stock image)

A mother claims a dog has attacked her two young children at a popular park in inner-city Sydney (stock image)

The alleged attack happened in the Sydney Park wetlands area in inner-city Alexandria

The alleged attack happened in the Sydney Park wetlands area in inner-city Alexandria

'Please be very careful in Sydney Park with kids. Be on the look out for the dog,' the mum ended the post.

Commenters urged the woman to contact police and the local council. 

NSW Police told Daily Mail Australia that they are yet to receive any reports about the incident.

Sydney Park is a popular park with extensive facilities, including off-leash areas, a large playground, children’s cycle track, skate park, wetlands, sports oval and outdoor fitness areas.