The US House Speaker Paul Ryan has urged Americans to produce more babies to prevent a collapse in the welfare system.

The Republican, a father of three, warned that the baby boomers who are now either dying or retiring aren't providing enough children to replace them.

Democrats have also made similar warnings, but in favour of inviting more immigrants to the US to help fill the gap.

Ryan also called on his fellow members of Congress to do more to help those struggling in the welfare system to get back into work, to enable them to afford to have children.

Speaking on 14 December, Ryan said: "This is going to be the new economic challenge for America: people. Baby boomers are retiring — I did my part, but we need to have higher birth rates in this country.

"Baby boomers are retiring and we have fewer people following them in the workforce.

"We have something like a 90% increase in the retirement population of America but only a 19% increase in the working population in American.

"So what do we have to do? Be smarter, more efficient, more technology... still gonna need more people.

In 2016, there were 62 births for every 1,000 women in the US of child-bearing age, a fall of 1% compared to 2015.

Ryan added: "And when we have tens of millions of people right here in this country falling short of their potential, not working, not looking for a job or not in school getting a skill to get a job, that's a problem.

Paul Ryan
US Speaker of the House of Representatives Paul Ryan arrives in Downing Street to meet Britain's Chancellor of the Exchequer Phillip Hammond, in central London, Britain 19 April 2017 REUTERS/Stefan Wermuth