Workers will remember Public Service Minister Faith Muthambi's R300 000 junket during the next round of wage negotiations at the end of the year, trade union federation the Congress of South African Trade Unions (Cosatu) warned on Monday.

"If there is money for minister's junkets, we expect that money will also be found for public servants, who carry this country on their backs," Cosatu spokesperson Sizwe Pamla said in a statement.

The Sunday Times reported that R300 000 was spent on flying 30 people to Cape Town to watch her budget speech in Parliament in May.

They reportedly included her son, sister, aunt, mother, former South African Broadcasting Corporation (SABC) board chairperson Ellen Tshabalala, and former SABC chief operating officer Hlaudi Motsoeneng's daughter, who she hired to work for her.

Muthambi told the newspaper the department asked her for a guest list. Other ministers said the guests should have had some connection to the department.

Cosatu called on the allegations to be investigated and for Muthambi to repay taxpayers' money.

"We find it bothersome that at a time when millions of poor people are struggling to survive and when public servants are being told about government’s austerity measures, the minister is splurging on her family without constraints," Pamla said.

Such "momentary lapses of common sense" were eroding trust in government. The administration seemed to value political loyalty more than efficiency.

"This supports the view that our current leadership is dishonest and cynical; and that the Batho Pele principles have been banished to the limbo of forgotten things," Pamla said.

The Democratic Alliance on Sunday said Muthambi had to repay every cent.

"'Meddling Muthambi', who is seemingly deeply compromised and who is the very same person who oversaw the demise of the SABC, is clearly at it again in her new portfolio," DA MP Desiree van der Walt said.

Chairperson of Parliament's public service and administration committee, Makhosi Khoza, said on Monday that Muthambi would be called to explain the expenses and alleged unfair recruitment processes in her department.

Parliament had previously found Muthambi to be "incompetent".

The #GuptaLeaks revealed that Muthambi allegedly sent emails containing confidential information about executive policy and the scope of her ministerial powers to Tony Gupta. This was shortly after President Jacob Zuma appointed her communications minister in 2014.

Two weeks ago, the Organisation Undoing Tax Abuse laid charges of high treason and corruption against Muthambi following these revelations.