The French telecoms company Orange is on "serious alert" after reports of a fresh spate of work-related suicides.

Since the beginning of the year, 10 of its employees have killed themselves – most for reasons "explicitly related" to their jobs, according to the company's own stress and mental health watchdog.

Orange was formerly the state-owned France Telecom, which reported a similar wave of deaths between 2008 and 2009. The number of suicides so far this year is almost as high as for the whole of last year, when 11 workers took their own lives.

Of the 10 deaths this year – three women and seven men, the youngest aged 25 – eight have been directly linked to work, according to the observatory for stress and forced mobility, which is responsible for monitoring work conditions at the company.

On Wednesday the French health minister, Marisol Touraine, called the new deaths worrying. "The company has to take the necessary measures. I know that the company and the unions are alert to this … we cannot leave the situation as it is," she told French radio.

The observatory was set up after the earlier wave of suicides caused widespread concern about working conditions and practices at the firm.

The company's former boss Didier Lombard resigned after 35 employee killed themselves between 2008 and 2009. He was lambasted and forced to apologise after suggesting suicide was a "fashion" at the company.

In 2012, Lombard was put under formal police investigation accused of installing "brutal management methods" that amounted to "moral harassment".

Le Parisien published an internal company document from 2006 in which Lombard allegedly told directors he was determined to cut 22,000 jobs, adding "I'll do it in one way or the other, by the window or by the door."

Lombard denied that his methods were the cause of the deaths. He remains under investigation.

An official report by the works inspectorate in 2010 blamed a climate of "management harassment" that it said had "psychologically weakened staff and attacked their physical and mental health".

Since then, Patrick Ackermann, delegate for the SUD union and member of the observatory, said the situation had eased, but last month the group issued a warning to management of a "dramatic worsening" of morale within the company to 2007 levels.

"For the last two years, the pressure from management has started again and working conditions have once more deteriorated," it said. Factors driving workers to depression included a reduced workforce being asked to produce better results, staff being obliged to relocate, the threat of site closures and job losses, and an atmosphere of increased competition between workers.

"Also, what we are seeing among mid-level directors is a return to old and brutal methods of management," the observatory said in a statement.

France Telecom was privatised in 2004, sparking a major restructuring and the loss of scores of jobs. The company, known since last year as Orange to match the name of its mobile phone operation, currently employs around 100,000, but has pledged further cuts to the workforce.

In a statement, Orange admitted there had been "several suicides" this year, adding: "Each of these acts is by its nature singular and stem from different contexts. But these situations remind us to be vigilant and for the need to repeatedly question the efficiency of the numerous preventative measures put in place several for the past few years."

The firm's mediator, Jean-François Colin, will meet with staff representatives on Friday to talk about "preventative measures" for those at risk.

France has a suicide rate of 14.7 per 100,000 inhabitants, well above the European average of 10.2 per 100,000 people, three times higher than in Italy and Spain and twice the rate in Britain. Of the estimated 10,000 suicides in France each year – 27 every day – at least 400 can be directly linked to stress caused by work, but employment concerns are believed to be a factor in many more deaths.

In May 2012, the left-leaning newspaper Libération published a manifesto signed by 44 French psychiatrists, sociologists and politicians calling for a national observatory to monitor suicide cases and understand the phenomenon with a view to better prevention.