Armed police were deployed to two small islands south of Invercargill on Friday after one man allegedly threatened residents and another reportedly shot a seal.

A 27-year-old man, who had access to firearms, was allegedly threatening residents of Potted Head on Big South Cape Island, off the southern tip of Stewart Island, police said.

The man was arrested and taken to Invercargill for a mental health assessment.

Later a 56-year-old man allegedly shot a seal then assaulted another man on Green Island.

The man was arrested and appeared in the Invercargill District Court yesterday where he was granted name suppression and remanded on bail.