Bale is the obvious danger man from a Scotland point of view ahead of the World Cup qualifier at Hampden on Friday night.
The Tottenham winger has scored 11 goals in as many games and McGhee believes he is as influential for Spurs as Lionel Messi and Cristiano Ronaldo are for Barcelona and Real Madrid respectively.
The 23-year-old's threat was reinforced to the Scotland players in October when they suffered a 2-1 defeat in Cardiff that ensures they are bottom of Group A and which effectively cost Craig Levein his job.
Bale won and converted a penalty equaliser and struck a sensational 25-yard winner in the final minute.
But McGhee and manager Gordon Strachan will remind their players that they got themselves into the driving seat and had a goal wrongly disallowed while 1-0 up, before Bale intervened.
McGhee said: "I've watched a lot of him recently and we obviously realise he's a huge threat. Any management team in the world at this moment coming up against Gareth Bale would give him serious consideration and, of course, we will do that and will plan to deal with him as best we possibly can.
"But we are at home, it's a World Cup qualifier and we feel that by exerting our influence on the game then that can possibly undermine his chances of being a big influence on the game."
McGhee added: "I said this a couple of weeks ago when we had a meeting: 'Let's imagine Gareth Bale isn't playing. You still have a very, very difficult game on your hands.'
"He is not the only player on the pitch we have to consider. We have to consider Wales as a team and a country trying to qualify for a World Cup. So we take them very seriously with or without him."