South African women have been urged to check regularly at their local registry offices, to see whether they have been married without their knowledge.
Corrupt officials have allegedly been performings weddings without a bride or groom
A "marriage verification campaign" was launched after 3,387 fake marriages were discovered, an official said.
Leslie Mashokwe said that criminals were using stolen identity papers to set up fake weddings to help foreign men get residence permits.
Two Bangladeshi men were last week arrested for allegedly fake marriages.
"Some women get mugged, others are robbed. Some people just lose their ID and it ends up in the wrong hands," said home affairs department spokesman Mr Mashokwe.
"They work hand-in-hand with corrupt officials."
Several women have recently had their wedding days ruined when they have been told they already had husbands.
Nicolene Saunders was refused a marriage certificate because she was already married, The Star newspaper reports on Monday.
"I don't know this man from a bar of soap," she said.
Last week, Bronwyn Gower went to pick up her new identity card and was astonished to find she was now "Mrs Fabian Oshi".
She was reportedly married on 14 April - a national holiday because of general elections, when all government offices were closed.
Officials, illegal immigrants and registered marriage officers, including priests, are all going to be investigated, under the "marriage verification campaign".
"We're telling [women] to go and check their status. If they got married in church, are they sure their marriage has been registered?" Mr Mashokwe said.
Crime syndicates reportedly sell fraudulent marriage certificates and residence permits for up to 5,000 rand ($833) each.
The buyers mostly come from Pakistan, Nigeria, Egypt, India, Bangladesh and Brazil, the home affairs department says.