Senanayake, who was reported for a suspect action during Sri Lanka's tour of England, was suspended from bowling in July 2014. After having his bowling action remodelled, he was re-tested officially at an ICC-accredited facility in Chennai last month. Williamson, also underwent testing at the Chennai facility. suspended in July. The ICC said the results for both bowlers showed that the level of elbow extension for all deliveries was within the prescribed 15-degree limit.
"It's nice to be cleared and to have the opportunity to bowl again," Williamson said. "I could become an option for Brendon.
"It's a good process to go through. It's a good initiative by the ICC. I enjoyed working on my bowling more, something I had not done in the past. That's probably why my action lost itself a bit. Now I am coming with a straighter arm and pursuing a new path with my bowling."
The ICC rules also state that if a bowler is cleared to play international cricket again, and is once more reported and found guilty of contravening the legal limits of flexion within two years of his original suspension, he will be suspended from bowling in international cricket for a minimum of one year.
Senanayake bowled each of his four variations during the Chennai Test, and will now be allowed deliver his full repertoire in internationals, a senior SLC coach said. The stock offbreak had given Senanayake most grief - the flex was over 40 degrees when delivering it during the Test that saw him banned - but the carrom ball, seam-up slider and the inswinger have also been worked on, and have been brought to within the legal limits.
"I'm very happy to be cleared, and I'm thankful to the board officials who helped me during this time," Senanayake told BBC Sinhala. "I'm also very grateful for the coaches who worked with me, and the selectors, who picked me in the preliminary World Cup squad, before the ICC report came."
His action was initially remodelled during a 10-day stint with human movement specialist Daryl Foster in Perth. Senanayake then continued his remedial work under the supervision of local coaches. He was allowed to play in Sri Lanka's Mercantile Cricket Association in August as part of the remedial process, and has more recently played for Sinhalese Sports Club in a club tournament in Singapore, as well as the Premier Limited Overs tournament in Sri Lanka.
Senanayake had been instrumental to Sri Lanka's limited overs success in 2014, and had been particularly effective in the World T20 and the ODI series in England. He will now be considered for World Cup selection, having been named in Sri Lanka's preliminary squad for the tournament.