Over Easter the A5 through the beauty spot was closed for hours as police dealt with dozens of illegally parked cars causing chaos and there are fears good weather will mean more problems this weekend.
North Wales Police, the Eryri National Park Authority, Traffic Wales and two councils have joined forces to tackle problems caused by visitors, many of whom travel from the Midlands.
On Good Friday 29 vehicles were towed from the roadside at Llyn Ogwen and nine from Pen y Pass on Yr Wyddfa - Snowdon.
Other vehicles received parking tickets.
Chief Inspector Gethin Jones urged people to heed the warning that anyone parked on a clearway or causing an obstruction will risk having their vehicle removed – at their own expense.
He said: “Irresponsible parking not only endangers pedestrians, cyclists and other road users but also prevents emergency vehicle access.
"We have previously witnessed pedestrians with young children, having to walk in the road in areas such as Llyn Ogwen and Pen-y-Pass because of the selfish actions of a minority – this is clearly unacceptable.”
During peak periods, visitors are encouraged to use park-and-ride facilities or dedicated parking areas. Spaces at Pen y Pass car park must be pre-booked.
A Sherpa bus service runs regularly and connects popular routes through the national park, while community electric buses also offer services in the area.
Visitors are also encouraged to explore other parts of the region that are less busy.