An elderly, wheelchair-bound amputee from northern NSW allegedly stabbed to death his 86-year-old wife before telling a Triple-0 operator he thought she was dead, police say.

Police have charged the 87-year-old man with his wife's murder after arresting him at their Hillcrest Avenue home in Goonellabah, near Lismore, sometime after 11am yesterday.

He allegedly stabbed his wife in the chest and neck before calling Triple-0 at 11.10am to report the incident.