New Zealand First leader Winston Peters has expelled Tauranga-based MP Brendan Horan from the Party's caucus after receiving "substantive information" relating to a family matter Horan is involved in.

Watch Peters talking to media in Parliament Buildings in the video above.

Watch the statement Peters made to Parliament in the video below.

"The information we have received leaves me in a position where I have no confidence in  Mr Horan's ability to continue as a member of parliament and he will be expelled from the NZ First caucus forthwith," Peters said.

He said it was Horan's duty to resign as a Member of Parliament.

Earlier in the day Horan's lawyers had issued a statement saying Horan wished to return to Parliament. He had been told by Peters to not come back until the family matter, relating to allegations about the estate of Horan's mother, had been sorted out.