The multimillion-dollar public bathrooms paid for by the city after Hurricane Sandy are already in such bad shape that they’re hanging together with duct tape at Rockaway Beach, bummed beach-goers say.

Some of the expensive new public bathrooms and lifeguard shacks — which cost the city $105 million — are rusty, cracked and jury-rigged with taped-up stair ramps after just a few months of use. The structures were supposed to be strong enough to withstand the next big storm — but some have railings held together with towels tied onto knots.