The International Cricket Council (ICC) announced the 29-year-old, one of the country's leading cricketers, failed an out-of-competition test in January.

He will be provisionally suspended from April 26 "unless he exercises his right to challenge the imposition of the provisional suspension before such date", the ICC said.

Shahzad, who has made a combined 116 appearances for Afghanistan across the Twenty20 and one-day international formats, could face a ban of up to four years.

The starting point will be two years if he can prove the violation of the ICC Anti-Doping Code was unintentional.

"Shahzad has to respond to the charge within 14 days," the ICC said in a statement.

"If he fails to do so, he will be deemed to have waived his entitlement to a hearing and admitted to having committed the anti-doping rule violation.

"The matter will now be dealt with in accordance with the process set down in the code, and until such time as the process is resolved, the ICC will make no further comment on this matter."

The wicket-keeper batsman is Afghanistan's leading Twenty20 run scorer with 1,779 runs at an average of 32.34.

Shahzad also holds his nation's record Twenty20 score after he hit 118 against Zimbabwe at Sharjah in January of last year.

He remains the only Afghan player to score centuries in both the one-day international and Twenty20 formats.

Clenbuterol is a steroid often used to treat asthma but is thought to have performance-enhancing benefits as it can help build lean muscle mass and burn off fat.