Close to 100 firms will be taking part in an event designed to test their readiness ahead of the Olympic and Paralympic Games today.

The Stress Test, organised by Canary Wharf Group and Deloitte, aims to get companies to recreate the measures they will have in place during the Games. These include staff trying out alternative travel arrangements and different ways of working.

The two-day test, which finishes tomorrow, will involve businesses looking at their IT, telecommunications and transport requirements and ensuring they can operate as normal during the Games, when there is likely to be some travel disruption.

Nearly half the firms taking part are in the financial services centre. Around a third of companies taking part have less than 250 employees, while a similar number have more than 1,000 employees.

Firms will also complete an online survey about their working practices with Deloitte, which has conducted research into Games Readiness.

In the latest research from January this year, staff unavailability was the biggest concern with 42 per cent of companies citing it as a worry during the Games, almost the same proportion as when asked last May.

Fears over general transport disruption have eased slightly, with 32 per cent of companies raising this as a worry compared with 35 per cent in May.

Deloitte also found 43 per cent of businesses intend to review their holiday policies ahead of the Games, while 33 per cent plan to review flexible working.

Mark Naysmith, Games readiness director at Deloitte, said: “On the busiest days of London 2012, there are expected to be an extra three million journeys a day on the public transport system.

“It is essential that companies across the city, large and small, have thought through how their business and their people will cope with this period.

“Whilst working from home is the most popular measure being tested, it will not be practical for all businesses who still need to maintain client service levels.

“Therefore, alternative measures such as changing the route to work, mode of transport, or time of journey will all be key to coping.”

Drew Gibson, business continuity manager at Canary Wharf Group, said: “The Stress Test is our warm up for the big event. Our plans aim to ensure that Canary Wharf and London remain open for business during the Games. Businesses across London will be better prepared for the Olympics if they prepare collectively.”