Word that Canada has expelled a diplomat from the African nation of Eritrea reflects the longstanding vulnerability of immigrants from conflict-ridden or economically poor countries are to extortion originating in their homelands.

Foreign Affairs Minister John Baird has declared Semere Ghebremariam O. Micael, head of Eritria's consulate general in Toronto, persona non grata and ordered him to leave Canada by Sunday, June 5, for levying a "diaspora tax" from Eritrean expatriates.

"Canada has repeatedly made clear to Eritrea to respect international sanctions and Canadian law," the Foreign Affairs and International Trade Department said Wednesday in a news release.

"The Eritrean government is welcome to propose another candidate to represent it in Canada, but that person must be prepared to play by the rules. Our resolve on this matter should not be further tested."

[ Related: Ottawa expels Eritrean diplomat over continuing 'diaspora tax' ]

The move follows news reports Micael's office was enforcing the Eritrean dictatorship's worldwide "diaspora tax" equal to two per cent of an expat's income, CBC News reported. The policy has been condemned by the United Nations.

There's nothing new in foreign political or armed movements trying to squeeze money out of expatriates. Fundraisers for the Irish Republican Army funnelled millions of dollars from Irish Canadians and Americans to oppose the British presence in Northern Ireland.

The separatist Tamil Tiger movement of Sri Lanka for years preyed on Canada's large Tamil community, using threats and intimidation to extort money for their decades-long, ultimately unsuccessful war to carve out an independent state on the South Asian island country.

Eritrea was a breakaway province of Ethiopia at the centre of a decades-long armed struggle that ended in 1991 with victory for the rebels. But with independence came dictatorship and continued tension along the two countries' border. Eritrea is seen as a troublemaker in the region.

CBC News reported the Eritrean government also demands a $500 tax described as "a donation of national defence against Ethiopian invasion."

Foreign Affairs warned the Toronto consul to stop soliciting and collecting the taxes or face loss of his diplomatic accreditation. Micael promised in a letter that he would comply but Eritrean immigrants told CBC News that the practice had not stopped. One said he was warned his family in Eritrea would be in trouble if he didn't pay.

"We had asked him at the early stages not to do this, it is contrary to our laws, but our information is that they continued doing it," Deepak Obhrai, Baird's parliamentary secretary, told CBC News. "And so we finally had to take action. We cannot allow our territory to be used for fundraising for other countries."

Eritrea has been subject to UN sanctions since 2009 but uses hard currency it extorts from expats to fund armed rebels fighting Ethiopia, as well as those tied to Somalia's Islamist al-Shabaab movement, CBC News said.

Human rights critics this week called on the TD Bank branches used by Micael to stop acting as conduits for the so-called tax money.

"They have stop this right away, immediately," said Ghazae Hagos of the Eritrean-Canadian Human Rights Group of Manitoba told CBC News. "They have to take measures to make sure that nothing like that will happen ever again."

[ Related: Tamil refugee facing deportation from Canada ]

Amnesty International Canada's Alex Neve echoed the call.

"Any company, including a big bank, should be very scrupulous about ensuring that it's not operating in ways that are going to contribute to, facilitate, and end up therefore being complicit in human rights violations," said Neve.

TD Bank emailed CBC News to say it was "investigating the claims," adding it has "rigorous controls to ensure we comply with Canadian economic sanctions regulations."

Some among the few thousand Eritreans living in Canada defend the practice. Yonas Zeru of Richmond, B.C., who Hagos fingers as one of Eritrea's tax collectors, called allegations of extortion baseless.

“You don’t need to pay [the] two per cent, if you don’t want to,” Zeru said, according to Global News. “You can count the people that have a problem with this.”