UPDATE 11am: The Opportunities Party has confirmed it will field a candidate in the Mt Albert by-election: Geoff Simmons (pictured below).

A former senior analyst at Treasury, Mr Simmons is general manager of The Morgan Foundation, and chief of staff for Mr Morgan's new political party.

Mr Simmons told NBR Radio that while TOP launched as a list party, John Key's resignation and National's decision to sit out the race had changed the picture.

"Not having National in this field means there's quite a large bunch of people with no-one to represent them."

National won the list vote in Mt Albert in 2014 (see tables below), but tactical voting by Green supporters helped Labour’s David Shearer to easily take the candidate vote.

TOP also unveiled a new slogan this morning: the Trump-esque "Make New Zealand fair again."

EARLIER: Gareth Morgan has called a press conference in Mt Albert later this morning – sparking speculation he or a proxy will stand in the by-election. Today is the deadline for nominations.

The Opportunities Party leader has previously indicated his party won’t stand in electorates, preferring to focus on making the 5% threshold in the list vote.

However, the lure of free publicity from the Mt Albert race seems like it’s been too much to resist.

Beyond a legion of bad cat jokes, Mr Morgan's entry to the race could raise the question: would he peel enough votes away from Labour for a Green win, or will he draw votes more-or-less equally from both parties?

In any event, it would liven things up.

There was speculation that National would choose to sit out the by-election to stoke Labour-Green infighting. But so far Jacinda Ardern and Julie Anne Genter have waged a faultlessly polite to the point of dull campaign, with their two parties even co-hosting a combined state of the nation event over the weekend.