The K1M 200 metres Olympic champion is arguably the biggest name still not guaranteed a starting berth in Rio de Janeiro after failing to make the final at last year’s World Championships in Milan.

Also still needing to qualify is Olympic silver medallist Saúl Craviotto of Spain, who like McKeever has only once managed to finish in the top two of a major race in the K1M 200m since London 2012.

Also hoping to have the opportunity to defend a top position on the Olympic podium is Ukraine’s Iurii Cheban in the C1M 200m and Germany’s Peter Kretschmer in the C2M 1000m.  

Kretschmer has changed partners since his London 2012 victory and will compete with Michael Muller when the action gets underway in Duisburg. 

Germany have won the C2M 1000m four times at the Olympic Games and claimed seven medals in total.

Only Romania and the Soviet Union have won more, with both nations collecting five golds medals and eight overall.

Two Olympic berths are up for grabs across all the men's singles events and the C2M 1000m, with a single crew able to qualify in the remaining races.

In women’s competition, three events will provide six boats quota places and eight athletes the chance of competing at Rio 2016.

This is the second and final opportunity to qualify for a spot on the startline in Rio with racing set to take place in the K1W 200m, K1W 500m and K2W 500m.

Kazakhstan’s Inna Klinova won the K1W 200m at the 2012 Olympic qualifying event, representing Ukraine.

She didn’t compete in the event for Ukraine at London 2012, however, as Inna Osypenko-Radomska did so instead and won silver.

Of the European boats in that 2012 final, Britain and Portugal will try to qualify for Rio in Duisburg.

London 2012 K1W 500m finalists Italy, Sweden and Ukraine, the runners-up, will aim to book their places, while Sweden will be vying to repeat their K2W 500m ticket-winning success from the 2012 Olympic qualifying event.

Tomorrow’s opening day of racing will be followed by finals on Thursday (May 19).