Employers’ groups have attacked trade union Amicus for giving workers advice on how to take a “sickie” so they can watch World Cup matches.

On its website, Amicus, the UK’s largest manufacturing union, has published advice entitled “World Cup fever – can you play away?” in which it provides tips on minimising the risk of punishment for taking time off to watch the action in Germany.

Under the headline “Just take a ‘sickie’?”, the site says: “It is quite difficult to prove that someone is not really sick if they have one day off; and most sick policies provide for the employee to self certificate for the first day off.”

Amicus advises workers to firstly try and book time off but if that fails it suggests employees should, with the help of a union negotiator, attempt to persuade managers “what a good investment it could be to find ways to let people watch the World Cup”.

If an employer does become suspicious of a worker’s absence and attempts to discipline them, the union says: “If you have a union representative they should be able to help you with your arguments an interpretation of procedures.”

Stephen Alambritis, from the Federation of Small Businesses, hit out at Amicus saying the guidance was not welcome given that absence already costs the UK economy £13 billion a year.

Speaking to the BBC, he said publishing such advice was “grossly unfair on all staff” and urged Amicus to withdraw the website content.

But Georgina Hirsh, head of legal affairs at Amicus, denied her organisation was promoting sickie taking.

“On balance the article is far from encouraging people to take sickies, and in fact we advise people that it’s a big risk for them to do so,” she told BBC Radio 4.

“I’m afraid the reality is – lots of people do take sickies whether it’s for the World Cup or not.”