It's one of Melbourne's top tourist activities, strolling under Luna Park's famous toothy smile.

From now on, however, those few steps into one of the city's most loved attractions will cost $2.

Management introduced the entry fee on Sunday, closing free access to Luna Park's picnic grounds and public toilets for those who don't buy ride tickets.

When Luna Park opened in 1912, it cost sixpence to enter the amusement park. But somewhere along the line, the fee was dropped.