* 12th straight rise comes ahead of parliamentary elections
* Ministry signals worse to come
By Brian Love
PARIS, May 30 (Reuters) - France had more jobseekers in April than any time this century as numbers rose for the twelfth month running, and the labour ministry said it was braced for more layoffs in the months ahead.
In a stark illustration of the economic challenges facing new Socialist president Francois Hollande, registered jobless in mainland France rose by 4,500 to 2.89 million, up 0.1 percent from March and the highest since September 1999.
Wednesday's readout from the ministry was the first since Hollande named an interim government in mid-May.
It comes just over a week from the opening round of a parliamentary election where the left hopes to consolidate his position by securing control of the lower parliamentary house.
There were clear signs that a number of corporate layoff plans had been held back during an election period, the ministry said.
"The government is fully mobilised in the face of layoff plans that have been announced or on the way in coming months," it added.
Hollande, elected on a tax-and-spend programme, has promised to create 150,000 state-aided jobs and recruit 60,000 staff in the national education service during his 5-year term but has stopped short of announcing targets for reducing joblessness.
The data is the most frequently reported domestic jobs indicator for France, although it is not prepared according to widely used International Labour Organisation (ILO) standards nor expressed as an unemployment rate of number of job seekers compared to the total work force.
The CGT trade union, one of the country's largest, told the government at a meeting on Tuesday that some 45,000 jobs risked being lost in the near term in France, where economic growth stagnated in the first quarter of the year.
That estimate, presented at a meeting between unions and the government, was described as "realistic" by Labour Minister Michel Sapin on Wednesday.
"There are genuine concerns. It's a matter of urgency in the case of some companies and those emergencies need to be tackled in a way that offers a future through dialogue," Sapin said in an interview on RTL radio.
Opinion polls suggest Hollande's camp will secure control of the National Assembly in the two-round election on June 10 and 17, after a decade of right-wing government.