Police condemn scrambler riders "pulling wheelies" on the M6
A spokesman for the North West Motorway Police said: "It really isn't big or clever and you're putting not only your own life at risk but that of others."
Police confirmed on Twitter that patrols from their Merseyside detachment had been drafted in to deal with the incident.
Several other drivers reported spotting the off-road bikes on Sunday.
Posting on the site, Nicola Richardson said the riders had been causing "mayhem" through Ashton.
And other motorists said the riders had been spotted along the East Lancs Road shortly afterwards.
Alison Bolton said: "They were on the East Lancs as well, going towards Liverpool at Carr Mill.
"There looked to be about 8-10 of them behaving erratically. Most of them not wearing helmets and pulling dangerous wheelies."
David Nicholl said: "It's like the Wild West in parts of Greater Manchester and Merseyside.
"I've been buzzed by these idiots before and its not pleasant, and having one play "dare" doing a wheelie towards me on my side of the road was terrifying."