WARSAW, Poland — An international human rights body on Friday criticized recently enacted legislation in Poland regulating the nation’s top legislative court, saying the law “gives excessive power to parliament and the executive over the judiciary.”

The Venice Commission, a group of constitutional law experts with the Council of Europe, the continent’s top human rights watchdog, issued its opinion during a meeting in Venice, Italy.

The Polish government refused to send representatives to the meeting, accusing the commisison of political bias and of refusing to take Warsaw’s position into account.

It is the latest development in a long-running crisis in Poland surrounding the Constitutional Tribunal, which is charged with evaluating the constitutionality of disputed legislation. The court therefore plays a key role in Poland’s system of democratic checks and balances.

The European Union, United States and many Poles also have expressed concerns about the Polish government’s attempts to change how the court works. The changes have effectively weakened the court’s ability to strike down disputed new laws governing other matters, including police surveillance and government control of public media.

Critics see it as part of a larger attempt by the government to centralize its power and accuse it of violating liberal democratic norms.

Prime Minister Beata Szydlo and other leaders say they have an electoral mandate to reform the country and must take control of institutions to remove the lingering presence and influence of political opponents who would stymie their mission.

Poland’s current ruling party, Law and Justice, has twice overhauled the rules governing the court since assuming power last year. Both attempts have sparked criticism.

The first law was struck down in March as unconstitutional by the Constitutional Tribunal itself. However, the government refused to publish the ruling in the official gazette, a step required for it to take legal effect. The overturned law also had been strongly criticized in an earlier opinion by the Venice Commission, which said it violated democracy and the rule of law.

In the commission’s opinion on Friday, it said that an amended version of the law adopted in July improves some of the earlier problems. But the commission also said that the improvements “are too limited in scope,” while other new provisions of the act “would considerably delay and obstruct the work of the tribunal, possibly make its work ineffective, as well as undermine its independence by exercising excessive legislative and executive control over its functioning.”

The provisions that troubled the commission included one which allows a case to be postponed for up to six months upon request by four judges. It also criticized a provision giving the prosecutor general — a government appointee — the right to block a hearing by his or her absence.

“Individually and cumulatively, according to the Venice Commission, the shortcomings show that instead of unblocking the precarious situation of the constitutional tribunal, the parliament and government continue to challenge its position as the final arbiter of constitutional issues and attribute this authority to themselves,” the commission said.