Woman, 25, missing in NSW bushland

Police hold grave fears for a young woman who's been missing in remote bushland in central NSW for three days.

Rocky Eiao, 25, walked off into bushland in Girilambone around midday on Friday after an argument with a man she was with, a police spokeswoman told AAP on Monday.

The man and another friend searched for her before alerting police on Saturday afternoon.

A full-scale search on Sunday using trail bikes, police rescue, SES and RFS volunteers failed to find Ms Eiao.

The search area covers about 45,000 acres of remote bushland because the man can't remember exactly where they were when Ms Eiao walked off, the police spokeswoman said.

Police were concerned for her safety because of extreme temperatures in the area.

A full-scale search on Sunday using trail bikes, police rescue, SES and RFS volunteers failed to find Ms Eiao.

The search area covers about 45,000 acres of remote bushland because the man can't remember exactly where they were when Ms Eiao walked off, the police spokeswoman said.

Police were concerned for her safety because of extreme temperatures in the area.