Super Typhoon Hagibis was forecast to hit the south-west of the country but has changed course and is now projected to hit the south-east near Tokyo and Yokohama.
According to the Japan Meteorological Agency, Hagibis is currently classed as "violent", with gusts as strong as 270kmh. It is forecast to weaken before it nears Japan but will still be "very strong".
The All Blacks are travelling to Nagoya by train on Friday afternoon for their match against Italy a day later at Toyota City, just over 300km south-west of Tokyo.
The matches most likely to be affected are the England v France game, a Pool C decider, in Yokohama on Saturday and the Japan v Scotland game on Sunday also at Yokohama Stadium. The latter is the match which will determine whether the hosts qualify for their first quarter-final.
Under tournament rules, if a pool match is cancelled due to a typhoon – Japan has about 20 a year – then it is ruled a 0-0 draw.
The team above which would be disadvantaged most by a draw is Scotland, who need to beat Japan in order to qualify for a quarter-final.
"We've obviously had reports," All Blacks assistant coach Ian Foster said.
"We get regular reports like everyone does. This report seems to be a little bit more serious than other reports. We'll just track it and watch it.
"It doesn't change any plans for us now but as it gets closer to the time I think what everyone hopes is that it doesn't disrupt anything or it doesn't cause any issues with the tournament. I guess we'll just have to cross our fingers and buckle down and hopefully, common sense prevails and if it does disrupt things that good decisions are made."
The typhoon would bring heavy rain and very high winds. Public transport could be cancelled as a precaution.
"While it is too early to determine the exact trajectory and impact, if any, of the typhoon at this early stage... we have a robust contingency program in place in the event adverse weather looks likely to impact fixtures," World Rugby said in a statement.