Following the death of Act candidate Neil Christensen, a byelection will be held. There will be at least 121 MPs in parliament for the next term, and the extra seat will almost certainly be National’s, writes Anna Rawhiti-Connell in this excerpt from The Bulletin, The Spinoff’s morning news round-up. To receive The Bulletin in full each weekday, sign up here.

A byelection in Port Waikato

Following the death of Act’s Port Waikato candidate Neil Christensen, a byelection will need to be held in the seat. The resulting domino effect will mean parliament has at least 121 MPs at the next term, and in all likelihood, National will gain an additional MP. As Stewart Sowman-Lund explains, the unexpected death of Christensen has triggered section 153A of New Zealand’s Electoral Act, and residents in Port Waikato will be heading back to the polls after this weekend’s election for a byelection. In a statement on Monday afternoon, the Act party said it was in mourning for Christensen, who was also New Zealand’s only registered specialist poultry veterinarian. “I wish to pay tribute to Neil, who was an infectiously charismatic and fascinating man,” David Seymour said.

Party vote in Port Waikato still counts

The Electoral Commission has been quick to stress that voters in Port Waikato should still vote as their party vote still counts, but voting for the local candidate in Port Waikato will be suspended, and any electorate votes already cast during the advance voting period will be nullified. A byelection will take place at a later date set by prime minister Chris Hipkins in consultation with other party leaders once he has considered information provided by the Electoral Commission.

Why another MP and why it will likely mean another MP for National

As constitutional expert Andrew Geddis explains, “The Electoral Commission must allocate a total of 120 seats amongst parties that cross the representation threshold after the general election (less any seats won by an independent candidate).” “The by-election in Port Waikato will then return an additional MP,” he says. The Electoral Commission has since confirmed this. As the Herald’s Claire Trevett writes, the extra seat created by the need to ensure 120 seats are allocated after the election will almost certainly be National’s. Port Waikato is a safe National seat held by Andrew Bayly. The prediction is that Bayly would win the byelection, and as he’s high enough on the list to get in as a list MP on election night, another National list candidate will gain a seat.

We could also be looking at a 122 or 123-seat parliament

For another round of electoral calculus, Trevett raises a scenario that depends on what happens with Te Pāti Māori. If Te Pāti Māori gets more electorate MPs than its party vote would qualify it for, it could result in a 122 or 123 MP parliament – and that would mean 62 seats were needed to get a majority rather than 61. So far, the only poll that points to an electorate seat win for Te Pāti Māori is the Whaakata Māori/Curia poll released last night that shows Te Pāti Māori co-leader Rawiri Waititi comfortably ahead in Waiariki, but there are some close races based on previous Whaakata Māori/Curia polling to date, and there’s more polling to come.

Finally, here are the last of the tent pole events this week:

• Tonight: The Press debate featuring the minor party leaders starts at 7pm tonight
• Wednesday: Last 1News Verian poll before election day
• Thursday: 1News leaders’ debate