A legal fight looks likely over the Wellington City Council's decision to make micro-chipping mandatory for all cats within 18 months.

Photo: 123rf

Campaign for Cats said it would seek a judicial review of the bylaw, which the council passed at a meeting this morning.

Campaigner Kent Duston confirmed the legal action, saying he hoped a ruling would set a nationwide precedent for all councils to follow.

"There seems to be quite a lot of lobbying of councils going on at the moment to get them to restrict cats, in ways that appear to be against the Local Government Act," Mr Duston said.

"We think that this is a matter for the government, not for councils through individual bylaws around the country."

The campaign's legal team was pulling together the necessary documents to apply for the judicial review, he said.