(Reuters) - Britain's Paralympic champion wheelchair racer David Weir has backed the decision to ban Russia from next month's Rio Paralympics for state-sponsored doping.

The Court of Arbitration of Sport (CAS) on Tuesday upheld the International Paralympic Committee (IPC) ban on Russia competing at the Sept. 7-18 event.

"It's probably the right choice if they've got evidence that most of the athletes are on a doping program," the six-times Olympic champion told British media on Thursday.

"It's a bold step by the IPC and definitely the right one if they've got evidence.

"Over the last few years I've started to doubt people, which you never want to do. You look at people's performances and think 'really?' and not 'wow'."

The six-times wheelchair London marathon winner said the drug-testing system was less stringent outside Britain.

"The doping policy needs to be a bit more thorough throughout disability sport. Not in the UK, because we're tested constantly, but throughout championships," the 37-year-old added.

"We've seen athletes getting caught and if it's happening in the mainstream, it's got to be happening in the Paralympics. When I was at the European championships I did four events and got tested once.

"Maybe it's manpower or funding. A lot of nations are throwing millions of pounds at medals and we want to deliver on a level playing field."

(Reporting by Nivedita Shankar in Bengaluru, editing by Ed Osmond)