Workers in a Russian region have been given today off to have sex in a bid to boost the birth rate.

Today has been declared the Day of Conception in Ulyanovsk, Lenin's birthplace, when couples are told go to home and multiply.

If they succeed they could win a car, cash or a fridge.

Under the city council's "Give Birth to a Patriot" scheme, those who give birth on June 12, Russia Day, will get a prize.

The winning couple of the grand prize - a locally made 4x4 car - are judged by a committee on criteria such as "respectability" and "commendable parenting".

The scheme is championed by the Ulyanovsk governor, Sergei Morozov.

"The leadership (of the country) is interested in the family," he told AP Television News.

Since the scheme started three years ago the region's birth rate has increased.

Low life expectancy, declining birth rates, a spike in emigration to other countries, a frayed healthcare system and other factors have contributed to a sharp drop in Russia's population since the 1991 Soviet collapse.

The world's largest country now has just 141.4 million citizens, making it one of the most sparsely settled nations in the world.

Experts expect the decline to accelerate, estimating that Russia's population could fall below 100 million by 2050.

Just 311 women signed up to take part in the first competition, in 2005, and qualify for a half-day off from work.

The following June, 46 more babies were born in Ulyanovsk's 25 hospitals compared to the previous June, including 28 born on June 12, officials said.

More than 500 women signed up for the second contest, in 2006, resulting in 78 babies being born nine months later, which was more than triple the region's daily average.

So far this year, the region's birth rate is up 4.5% compared to the same period last year.

Andrei Kartuzov, who won the last "make a baby" grand prize along with his wife, Irina, said they had been planning to have another child anyway when they heard about the contest.

The campaign "is a good help for people, especially for those living in villages", he said. "If they hold such actions every year, then maybe we will have (more children) growing up and Russia will be bigger."

In his state of the nation address last year, the president, Vladimir Putin, said the demographic crisis was the country's most acute problem and announced a broad effort to boost the birth rate, including cash subsidies for couples giving birth to more than one child.

Women who give birth to their second or third child receive 250,000-ruble (£4,800) vouchers that can be used to pay for education or home repairs.

· This article was amended on September 20 2007. June 12 is Russia Day, not Lenin's birthday. This has been corrected.