Qatar reiterated on Sunday that the country denies any involvement in a corruption case being investigated by Belgian authorities involving people linked to the European Parliament.

Belgian authorities have charged four people linked to the European Parliament over allegations World Cup host Qatar lavished them with cash and gifts to influence decision-making. Qatar has previously denied any wrongdoing.

A statement on Sunday by a diplomat from Qatar's mission to the European Union said "preconceived prejudices" led the parliament to vote on Thursday to suspend all work on legislation involving Qatar and to bar Qatari representatives from its premises.

The suspension affects legislation linked to visa liberalisation, an EU-Qatar aviation agreement and planned visits until the allegations have been confirmed or dismissed.

"The decision to impose such a discriminatory restriction...will negatively effect regional and global security cooperation, as well as ongoing discussions around global energy poverty and security," the diplomat said.

Qatar had been "exclusively criticised and attacked" in the investigation and was deeply disappointed that the Belgian government "made no effort to engage with our government to establish the facts" the statement said.

A spokesperson for the European Parliament declined to comment on the accusation.

Spokespersons for the Belgian Justice Ministry and the Federal Prosecutor's Office did not immediately react to requests for comment.

The ministry said on Wednesday its intelligence service worked closely with other European countries for more than a year to uncover the graft scandal.