By Inti Landauro

MADRID (Reuters) -Spain has opened an investigation into an unidentified holiday apartment renting platform for failing to delete thousands of rental offers in another attempt to curb a business blamed by many for housing shortages and soaring prices.

The probe is part of a general crackdown on tourism rentals via sites such as Airbnb and Booking.com which many Spaniards say is creating excess tourism, cramping the housing stock and making renting unaffordable for locals.

A Consumer Rights Ministry’s department had since the summer ordered the platform to remove thousands of listings deemed “illegal advertising” without licences for tourism use, a ministry spokesperson said.

As the adds stayed up, a disciplinary process began, with the platform facing a potential fine of up to 100,000 euros ($104,940.00) or four to six times the profit made on the practice, a ministry statement said.

“It is the ministry’s responsibility to make sure no company in this country is above the law,” Minister Pablo Bustinduy told reporters on Wednesday.

A fine by the ministry can be challenged in court.

Airbnb and Booking.com, the largest platforms operating in Spain, which is one of the world’s biggest tourist destinations with more than 80 million visitors a year, did not immediately respond to requests for comment.

Spain’s toughest move so far in the curb came from Barcelona’s mayor Jaume Collboni when in June he ordered a total ban on tourism rentals by 2028.

The ban is being challenged in courts by associations representing tourist apartment owners.

Airbnb urged him to reconsider, arguing that the ban only benefits the hotel sector while failing to address excess tourism and the housing crisis.

The consumer rights ministry last week also launched an investigation into agents who handle sometimes hundreds or thousands of platform accounts on behalf of owners.

Other European countries including Italy or Croatia have also taken measures to limit the growth of tourism rentals.

($1 = 0.9529 euros)

(Reporting by Inti Landauro, editing by Aislinn Laing and Andrew Cawthorne)