Immigration workers due to strike tomorrow should go to work to “show what they are capable of”, Jeremy Hunt said today.
Border officials are expected to abandon their posts on what is tipped to be the busiest day at Heathrow Airport as thousands of extra passengers arrive for the Olympics.
The Culture Secretary criticised the planned action by the Public and Commercial Services union, which will be challenged today in the High Court.
Mr Hunt said: "For an immigration officer - and I'm sure the vast majority of immigration officers feel this way - Thursday is one of the biggest days in their professional career.
"It is the day when the eyes of the world will be upon them and the welcome we are giving to the rest of the world.
"The vast majority of them will want to do a really good job and show what they are capable of."
Tomorrow's action is due to go ahead even though only one in five union members took part in a strike ballot - with just over half of those backing a walkout.
Mr Hunt believed enough members would break the strike to ensure Games officials, athletes and VIPs do not suffer too much disruption.
"We can be very confident in the contingency plans we have in place as of this morning," he told BBC Radio 4's Today programme.
"We need 550 people to maintain a full immigration desk policy at Heathrow which means we can get people through in the shortest possible time and we have 584 shifts now confirmed for Thursday, despite the strike."
Mr Hunt said fears Heathrow would grind to a halt because of the extra passengers had so far failed to materialise, and he hailed the situation at the hub airport as "a tremendous success".
He refused to criticise G4S guards, turning his fire on the company's executives who failed to honour their contract to supply thousands of security staff to protect the Games.
"We were very angry with G4S management but not with the G4S workers," he said.
"I just think it's really important we don't demonise them, because they are part of the mix."
The Government yesterday ordered another 1,200 troops to mobilise before the Olympics, with the Culture Secretary today insisting: "We just didn't want to leave anything to chance."