Johannesburg - Swaziland will never repay South Africa its R2.4bn loan, despite claims it will come from future revenues, Cosatu said on Friday.
"It (the loan) provides breathing space for the regime," the trade union federation's deputy president Zingiswa Losi told journalists in Johannesburg.
"It does not address the need for democratisation in any serious manner."
Losi said Swaziland already owed the International Monetary Fund and the World Bank R70bn.
Cosatu called on the South African government to rethink the bailout and disassociate itself from the Swazi regime.
"We did not meet a single person in Swaziland who said that the bailout was welcomed," Losi said.
"On the contrary, everyone we met, both inside and outside of the democracy movement, said that the bailout will actually make matters worse."
Losi and Cosatu's deputy international secretary Zanele
Matebula were arrested in the southern Swazi town of Siteki on Thursday
when they tried to address a crowd during a pro-democracy march.
They were deported back to South Africa. Police fired teargas and rubber bullets to break up the protest.
Losi said during the deportation she and her colleagues had to give the Swazi police all their details, including residential addresses.
"They said they will check up on us and follow us to make sure we didn't lie. We are fearing... we don't know about security at home. We have told the people of Swaziland we will be back."