Four New Zealand Catholics have been invited to Rome by the Pope to take part in discussions on marriage and the family.

Pope Francis has made efforts to reach out to the margins, and part of that is to include geographically diverse participants in such events.

Cardinal John Dew, Palmerston North's Bishop Charles Drennan, the chair of Parents Centres New Zealand Sharron Cole, and bioethics expert Dr John Kleinsman will attend the Synod.

The church describes the invitation as significant in number for a small country, especially one with a small Catholic population.

The Bishop of Tonga and three Australian representatives will also attend.