LISBON, Sept 5 (Reuters) - Chinese technology giant Huawei has filed a lawsuit with a Lisbon court against a resolution by Portugal's cybersecurity council CSSC that effectively bars operators from using its equipment in high-speed 5G mobile networks, the company said.

The CSSC is the prime minister's consultative body and its resolution, although not naming Huawei directly, was seen as a blow to efforts by Huawei to enter standalone networks in the 5G market in Portugal, and extend existing contracts on 4G platforms on which the new technology is based.

Europe and the U.S. have concerns that Chinese involvement in critical infrastructure could compromise security. Beijing and Huawei reject such suggestions.

"Huawei Portugal seeks protection of its legitimate interests and legal rights under the law as a company duly established in Portugal," Huawei replied to Reuters when asked about the lawsuit.

The justice ministry's portal Citius shows that the lawsuit was filed at the Lisbon Administrative Court on Aug. 31.

Huawei told Reuters it hopes the court will "remedy the multiple violations" of its rights, and the "significant detrimental impact on the company and its partners" from the resolution.

The secretary of state for digitalisation, Mario Campolargo, who chairs the CSSC, told Reuters earlier that the deliberation in May was based on an independent, strict security assessment following European Union guidelines, and did not specifically target Chinese suppliers.

The assessment had warned of a "high risk" to security of networks involving 5G technology "from suppliers or providers that are headquartered in a country where the government exercises control, interference or pressure on its activities in third countries".

It also cited risks when the country is not an EU, NATO or OECD member.

Portugal's main operators, Altice, NOS and Vodafone have already said they would not use Huawei's equipment in 5G core networks.

The CSSC said it had not been notified of any legal action, and that the operators were already developing their respective implementation plans, "mitigating threats and risks" in line with the resolution, to be presented to the telecoms regulator ANACOM.

"(5G networks) should be scrutiniseable, transparent and reliable for the state, citizens and companies," it said. (Reporting by Sergio Goncalves; Editing by Andrei Khalip and Jan Harvey)