French presidential candidate Emmanuel Macron was seen as the most convincing of the top five election contenders in a TV debate, an opinion poll suggested.

A snap online survey by Elabe pollsters put Mr Macron (29%) ahead of leftist Jean-Luc Melenchon (20%).

Melenchon was only a point ahead of conservative Francois Fillon and the far-right Marine Le Pen, who were tied in third place.

According to the poll, viewers felt Socialist candidate Benoit Hamon came last in the debate - with only 11% suggesting he was the most convincing.

The debate - which lasted almost three-and-a-half hours - is the first of three ahead of the first round vote on April 23rd.

Macron and Le Pen are the favourites to progress to the second round ballot in May, and the debate saw the pair clash on several topics.

Reuters reports that Macron accused Le Pen of failing voters 'by twisting the truth' over the rise of radical Islam in France, while Le Pen claimed Macron's rhetoric 'is completely empty'.

Macron - who is running under the progressive En Marche! banner - has continued to gain support in recent weeks.

Fillon - once the runaway favourite - has been hit by a series of controversies that has shown his support dwindle.

The left vote, meanwhile, has been split between Mélenchon and Hamon. It has been complicated further by the increasing popularity of Macron, who has been attempting to bridge the gap between the left & right.

While Le Pen is widely expected to progress through the first round of voting (she has consistently polled in the 26-27% range), polls have shown she is unlikely to win in a second round face-off with either Fillon or Macron.

Polling has indicated that Macron would have a lead of 20 points or more over the far-right candidate if both progress.