LONDON, July 4 (Reuters) - Former Russian president Dmitry Medvedev said on Tuesday that 185,000 new recruits had joined the Russian army as professional contract soldiers since the start of the year, as Moscow tries to beef up forces that have suffered big losses in Ukraine.

Last year Russia announced a plan to boost the size of its armed forces by more than 30% to 1.5 million combat personnel, an ambitious task made harder by its heavy but undisclosed casualties in the war.

Posters urging people to join up as contract soldiers are plastered throughout Russian cities, and TV adverts frequently pump out the same message.

"According to the Ministry of Defence, from January 1 to July 4, more than 185,000 people were accepted into the ranks of the Armed Forces, of which about 109,000 are in the reserve, as well as other categories of citizens who are called up to serve under contract," Medvedev said.

In a video posted on Telegram, he said that almost 10,000 new recruits had joined up in the last week since a brief mutiny by the Wagner mercenary group, whose fighters were given the option of signing on as regular soldiers.

"I want to specifically note that the attempted armed rebellion did not change the attitude of citizens to contract service in the zone of the special military operation," Medvedev said, referring to the conflict in Ukraine.

President Vladimir Putin ordered a "partial mobilisation" of 300,000 reservists last September, prompting hundreds of thousands of others to flee Russia in order to avoid being sent to fight. Putin has said there is no need for any further mobilisation.

Medvedev, appointed earlier this year to a role overseeing Russia's domestic military production, has said that factories are working round the clock to supply the army in Ukraine.

In Tuesday's comments, he proposed that assets seized from criminals, including high-speed boats and cars, should also be handed to the military.

He said prosecutors, the FSB security service and other agencies should work with the Defence Ministry to "take measures to transfer such equipment to our troops as soon as possible".