EU countries will from Tuesday begin rolling out tougher laws against online operators who play fast and loose with consumers, including those harvesting personal data or deploying bots to snap up tickets.

The consumer protection rules, from an EU directive to be implemented in every country in the bloc within the next two years, aim to rein in "rogue traders and online tricksters," the EU commissioner for values and transparency, Vera Jourova, said in a statement.

They will tackle some of the practices that savvy internet users are increasingly concerned about. Measures include:

- Banning traders from using automated online bots to buy thousands of tickets for concerts or sporting events and then resell them at inflated prices.

- Making sure price reductions are genuine by having sellers give the price of at least a month earlier as a reference.

- Informing consumers when the price they are given online is based on their internet browsing pattern, so they know it might be higher than that offered to someone else on the same site.

- Banning traders from having fake consumer reviews posted on their websites.

- Letting consumers know how search results in online marketplaces and price-comparison sites are ranked, including whether the top results they see were paid for by merchants.

The measures aim to boost consumer protection online and will impact internet vendors tapping into the EU market
The measures aim to boost consumer protection online and will impact internet vendors tapping into the EU market AFP / ISSOUF SANOGO

- Having sites offering "free" services tell consumers about what personal data is being collected and how it is used -- and giving them the right to cancel online contracts within two weeks.

The rules will impact online vendors who tap into the EU consumer market made up of 500 million people, including US internet goliaths such as Amazon, Google and Facebook, which have already run afoul of tighter competition and data-privacy rules in Europe.

"Breaking EU consumer rules on large scale may cost a company a big fine of at least four percent of annual turnover," EU Justice Commissioner Didier Reynders said in the statement. "This will be a sufficiently dissuasive and effective penalty to prevent dishonest traders from cheating."

Jourova said: "I strongly encourage all member states to ensure that the new rules are implemented without delay."

The new laws will add to an expansion of consumer protection in the EU that has already seen Brussels impose rules to do away with mobile phone roaming charges within the bloc as well as setting out compensation rights for airline passengers facing long delays or cancellations.

The directive applies to all EU members -- though Britain is set to leave the bloc at the end of this month because of Brexit, meaning it has to decide whether or not to mirror EU consumer regulations in its own domestic laws.