Gerry Brownlee will stand in for National Christchurch Central candidate Nicky Wagner at an electorate debate on Wednesday.

Foreign Affairs Minister Gerry Brownlee will stand in for a party colleague at an electorate debate this week, but will miss at least three similar contests in his own seat.

Brownlee, the National MP for Ilam in Christchurch for 21 years, has agreed to appear in place of Christchurch central MP Nicky Wagner at a candidate debate at the Ara Institute of Canterbury on Wednesday.

Wagner has attended other electorate debates, but could not make this one because of a scheduling conflict.

GEORGE HEARD/STUFF Wagner, the incumbent MP for Christchurch Central, cannot attend the Ara debate due to a scheduling conflict.

Brownlee appears to have had more demands on his time. He has missed two debates for Ilam candidates this month and will miss a third at the University of Canterbury on September 12. During the 2014 election campaign he was criticised by opponents for missing an Ilam candidate debate.

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"Gerry obviously is Minister of Foreign Affairs, which takes him away quite a bit," a Brownlee spokeswoman said.

IAIN MCGREGOR/STUFF Labour Christchurch Central candidate Duncan Webb has been a vocal critic of the rebuild, particularly on insurance matters.

"Obviously if he can attend, he attends, if he can't attend, or he's not in the country, he can't attend."

Brownlee declined the invitation for the university debate some time ago, she said, citing a longstanding commitment in Auckland that day.

Wednesday's debate is expected to take on a distinct rebuild flavour with Brownlee's presence.

Wagner has been the Greater Christchurch Regeneration Minister since May, but Brownlee held the position, and that of Earthquake Recovery Minister, for more than six years and has most often been the face of the Government's role in the city after the 2010 and 2011 earthquakes.

He will face Labour candidate Duncan Webb, a sharp critic of the rebuild and Wagner's chief rival for the central seat.



"I've let my network know and some of my network is very interested in the rebuild," Webb said.



​"They may well want to ask some rebuild-focused questions."

The debate will follow a question-and-answer format. Other candidates attending include the Greens' Peter Richardson and Doug Hill of The Opportunities Party.

The city's rebuild has gathered pace as an election issue in recent weeks.

Prime Minister Bill English announced a new contractor for the city's convention centre and pledged $120 million towards a new stadium.

Labour leader Jacinda Ardern was in the city on Sunday to announce her party would, if elected, put up a $300m capital fund for Christchurch.

The debate will be held at noon in the Rakaia Centre on Madras St.