If you're thinking of heading off to the beach on the Hibiscus Coast with liquor to celebrate Crate Day, the warning from police is don't.

A 48 hour liquor ban will be in force over Saturday and Sunday and there'll be consequences for anyone breeching the ban.

It will be in effect for all beaches, foreshore areas and parks from Hatfield’s Beach around the Hibiscus Coast and all of the Whangaparaoa Peninsula.

Crate Day is a tradition of sharing a crate of beer with your mates to celebrate the first Saturday of summer.

But police say partying last year turned ugly.

Thirty arrests were made at Stanmore Bay and they attended a number of serious incidents.

It included the assault of a police officer, people being comatose from binge-drinking, serious assaults and people suffering deep cuts to their feet from broken bottles.

Last year, emergency department doctors described National Crate Day as the worst shift they've worked in their lives.

After being inundated as a result, staff at Waikato Hospital's emergency department are calling for a national ban.

Director Dr John Bonning said a surge started around 10pm on Saturday and peaked at 2am.

He said many of those they cared for were aged between 16 to 23.

Dr Bonning said some were unconscious and injured and it made it very difficult for doctors to deal with other non-intoxicated people.

He said there were still people waiting to be seen by a doctor at 8am on Sunday morning.

Dr John Bonning says some were demanding and quite rude.