French Prime Minister Manuel Valls was pictured today sweating uncontrollably while facing down hecklers during a speech in which he promised to stick to his party's pro-business reforms.

Despite managing to complete his comments without major disruption, Valls looked exhausted after the trying discussion left him wet from head to toe.

And by the end of the public appearance, he needed to wipe himself down with a towel as his white shirt stuck to his body.

French Prime Minister Manuel Valls' white shirt turned see-through after he began sweating uncontrollably

After finishing his speech and facing down boos and hecklers, a drenched Valls gave the crowd a wave goodbye

Valls pictured delivering his speech the members of the Socialist party, many of who booed him for his economic policies

The Prime Minister began looking increasingly sweaty midway through his business reforms speech

At the end of the event, Valls needed a hand towel which he used to wipe himself down

He told the Socialist party members he would stick to pro-business reforms, despite heckling and booing by activists showing the divisions over economic policy.

A small group of young party members had booed Valls at a dinner yesterday and called for the resignation of Economy Minister Emmanuel Macron, whom they accuse of favouring business over Socialist ideals.

Many hardcore party members are uneasy about Macron, who epitomises the pro-business approach adopted by President Francois Hollande at the beginning of 2014 and with which Valls, the favourite of the left wing of the party to succeed him as president, is also associated.

Rebel backbenchers were very vocal during the three-day meeting and warned that they wanted their demands met in the 2016 budget bill, including tens of billions of tax cuts for businesses, due to be unveiled next month.

A party spokeswoman confirmed there had been 'a few boos' when Valls walked through the room at the behind-closed-doors dinner.

He also was heckled during his speech today when he said labour laws had become so complex that they had become inefficient.

However, Valls told the party the government was pushing on.

Valls was also heckled when he said labour laws had become so complex that they had become inefficient

Valls' economic stance could complicate his bid to get re-elected as parties prepare for the presidential ballot

First secretary of the French left-wing Socialist Party Jean-Christophe Cambadelis (right) and French Prime Minister Manuel Valls applaud after Valls delivered his speech

'We are pressing ahead with the deep reforms our economy needs,' Valls said. 'We won't be swayed.'

While pressure on Hollande to change tack from his party is unlikely to change the core of his policy despite France's economy slowed to a standstill in the second quarter, it could complicate his bid to get re-elected as parties prepare for the presidential ballot.

Hollande and Valls have said they would stick to a policy that puts a lid on public spending to meet EU budget targets, but they have also showed they are willing to compromise. They announced earlier this month that the 2016 budget would contain tax cuts for households.

The latest row over economic policy started when Macron on Thursday criticised France's cherished 35-hour working week, saying the Socialist party was mistaken in thinking that France would fare better if people worked less.

The was move decried as a 'provocation' by PS secretary-general Jean-Christophe Cambadelis.