The World Cup final will screen at 4pm on Saturday, October 31 at Twickenham in London - which is 5am New Zealand time - at which point most runners will be on the ferry to the Devonport start line.
In a statement yesterday, marathon event organisers said they had put "much effort into exploring various alternatives with the associated authorities". However, they were "unable to support these due to the impact on traffic levels, particularly on the Auckland Harbour Bridge".
The Herald understands few dates were available to organisers - the weekend after is the V8 Supercars New Zealand round at Pukekohe.
It is believed the the previous weekend, Labour Day, was offered but rejected because it clashes with the rugby semifinals and sponsors were not supportive. Finding volunteers for a long weekend may have also been an issue.
Organisers said they had worked with Sky TV to put a big screen at the start line in Devonport - but only if the All Blacks were in the final.
Those doing the half marathon, which starts at 6.50am, should be able to watch the final before the race.
"For marathoners, we plan on keeping you updated throughout your time on the course," the organisers said.
"We're celebrating this special event in true rugby style. Become an active supporter of the All Blacks and dedicate your run in support of their quest for victory," a message to potential entrants said.
The race appears to be lagging behind in sales, with the message including a push to sell tickets. "Don't miss your opportunity to be part of the iconic Auckland Marathon during a memorable year."
Sports events head to head: November 1, 2015
5am: Rugby World Cup final begins
6am: Full Marathon (42km) begins as game is still being played.
6.50am: Half Marathon (21km) begins.
