Ministers are "whipping up hysteria" over the planned strike by border agency staff, union leader Mark Serwotka has said.
Writing on The Huffington Post on Friday afternoon, the general secretary of the Public and Commercial Services Union said the government was guilty of deliberate "scaremongering" in order to distract attention away from the fact it was cutting a third of the border staff.
"Yesterday when we announced that border officials, passport workers and other Home Office staff had decided to strike on the day before the Olympics opening ceremony, ministers went into overdrive," he says.
"We were treated to not just one, but three government ministers wading in, bizarrely, to both whip up hysteria about the perceived impact of a strike ahead of the Games and to play down its effects."
He adds: "This is scaremongering, designed to deflect attention away from the root causes of the dispute: namely that the Home Office is cutting a third of its staff, including thousands at the borders, and bringing in a private company to undertake sensitive immigration and customs work - at a time when G4S has given us all a textbook lesson in the failings of privatisation."
Serwotka also accuses immigration minister Damian Green of behaving in a "reckless and provocative" manner over negotiations.
Thousands of staff at the Home Office, including airport immigration workers, are to stage a 24-hour strike in a row over jobs, pay and other issues.
Home secretary Theresa May yesterday branded the PCS strike decision "shameful".
She said: "They are holding a strike on what is one of the key days for people coming in for the Olympic Games.
"We will of course put contingency arrangements in place to ensure we can deal with people coming through the border as smoothly as possible."
While Labour leader Ed Miliband has urged border staff not to strike on the eve of the Olympics.
The Labour leader said he was "totally against" next Thursday's planned walkout, the day before the Games officially open.
The action will hit border controls at ports and airports including Heathrow, threatening disruption to people travelling to London for the Games.
But Miliband, who has been criticised for his close links to the unions, branded the strikes "totally wrong".
He said: "I don't think they should be happening. Nothing must be allowed to disrupt the Olympic Games.
OVer the weekend the Labour leader spoke alongside Serwotka at the Durham Miners' Gala, however the PCS is not affiliated to the Labour Party.
"I implore anybody involved in these strikes not to go ahead with them. I don't think it is right for the country, I think it will cause disruption and I don't think it's what people want to see," Miliband said today.
Speaking on a visit to Corby in the East Midlands, he added: "It certainly won't win any sympathy from the public for the cause that people who are thinking about going on strike are putting forward."