A mother has died two days after her former partner allegedly attacked her in her home on the NSW Central Coast.

Ettalong Beach woman Blair Dalton, 35, was left in a critical condition after Lance Pearce, of St Clair, allegedly strangled and suffocated her on Tuesday evening.

Police were called to the Picnic Parade home Ms Dalton shared with her young child and found her with critical injuries.

Police performed CPR on Ms Dalton until NSW Ambulance paramedics arrived and took her to Gosford Hospital, where she died on Thursday night.