The Canadian government used a powerful new legal weapon — The Magnitsky Act — for the first time Friday, slapping sanctions on 52 officials from three countries: Venezuela, South Sudan and Russia.

The new law is named after Russian lawyer Sergei Magnitsky, who died in prison after he was arrested for an alleged tax fraud.

The U.K.-based businessman he represented, American-born Bill Browder, says Magnitsky was murdered by officials who wanted to cover up the fact that they had stolen $230 million in taxes paid by his company, Hermitage Capital, then the biggest foreign investor in Russia.

Browder has since devoted himself to persuading Western countries to pass a version of a U.S. law named for his former lawyer. The law was originally aimed at the corrupt Russian officials who were most closely involved in the Magnitsky case, but it also allows for the application of sanctions against corrupt officials of any government.

While Canada has always had discretionary powers to sanction any government it sees fit, the Magnitsky Act goes further, giving the government powers to freeze assets owned by individuals, if the government believes them to be involved in corruption, money laundering and rights abuses in their own countries.

The world's newest nation, South Sudan, is the first one named by Canada under the Magnitsky Act.

Three South Sudanese figures, blamed by the international community for their part in the violence that has wracked the country since it achieved independence in 2011, are in the Liberal government's crosshairs. They are former chief of staff of the Sudanese People's Liberation Army Paul Malong Awan, deputy defence chief Malek Reuben Riak Rengu, and Minister of Information and Broadcasting Michael Makuei Lueth.

Lueth is accused for using the country's airwaves to foment ethnic violence, as well as planning an attack on UN peacekeepers.

All three men were already targeted for sanctions by the U.S. Treasury Department in September.

Venezuela's corrupt ruling clique

Venezuelan President Nicolas Maduro, whom Canada has accused of steering his country "deeper into dictatorship," and many of his senior officials were already sanctioned by Canada on Sept. 22 for their role in gutting democracy and rule of law in the country.

Those sanctions were aimed at punishing senior politicians of the ruling United Socialist Party of Venezuela after they responded to their defeat in legislative elections by stripping Venezuela's congress of its powers and transferring them to a "constituent assembly" stacked with party loyalists.

Also sanctioned were officials in the National Electoral Commission — themselves United Socialist Party of Venezuela loyalists — who helped to enable that act of constitutional trickery and have played a major role in undermining the integrity of Venezuela's democracy.

Venezuela's President Nicolas Maduro, centre, shown with supporters after the announcement of the results of the nationwide election for new governors. (Miraflores Palace/Handout via Reuters)

Today's sanctions under the Magnitsky Act target 19 people in Venezuela, including Maduro, Vice-President (and possible heir apparent) Tareck El-Aissami, a number of cabinet ministers and the two surviving brothers of former president Hugo Chavez. Some of the most senior officials in the country were already sanctioned in November.

"These individuals are responsible for, or complicit in, gross violations of internationally recognized human rights, have committed acts of significant corruption, or both," said an official from Global Affairs Canada in a note explaining the sanctions.

Several of the Venezuelans named have been implicated in drug-trafficking, a sideline that has enriched many of Venezuela's socialist elite. Two nephews of the Venezuelan president's wife were convicted in a New York court last year of conspiracy to traffic nearly two tonnes of cocaine into the US. Both have lost their appeals and face the possibility of life terms when they are sentenced next month.

Russians tied to Magnitsky case

Thirty of the 52 individuals sanctioned today by Canada are Russians — all of them accused of involvement in the Magnitksy fraud and murder, or its subsequent coverup.

They include tax officials who had overall responsibility for the case, such as Interior Ministry Lieutenant-General Oleg Logunov and his subordinate Natalya Vinogradova, who is accused of intervening to deny Magnitsky medical treatment.

Also named are prison officials who presided over the institutions where Magnitksy was held in deplorable conditions. And there are four judges who are accused of manipulating the case before them to deny Magnitsky his rights and protect his abusers.

Sergei Magnitsky's son Nikita Magnitsky and his mother, Natalia, watch as Bill Browder responds to a question during a news conference on Parliament Hill in Ottawa on Wednesday. Browder has campaigned for governments around the world to adopt the legislation. (Adrian Wyld/Canadian Press)

One of the names on the list is a banker, Dmitry Vladislavovich Klyuev, who is accused of helping to launder the proceeds of the $230 million fraud. Some of the money is thought to have been moved overseas through accounts Klyuev controlled in Cyprus. Some of the money may have made its way to Canada.

Russia has warned Canada that it will respond to the passage of what it sees as a hostile piece of legislation, and Friday's sanctions are unlikely to pass without retaliation.

In 2014, after Canada slapped sanctions on senior Russian military and political figures it accused of fomenting war in Ukraine, Russia retaliated with sanctions on 13 Canadians, including politicians from all three main federal parties.

One of them was Chrystia Freeland, then an opposition MP. Russia pointedly declined to remove Freeland from its sanctions list when she became foreign minister.