"We are conducting tests on all the 30 probables announced for the Twenty20 World Cup and these tests are conducted on Pakistan Cricket Board regulations, which are now WADA (World Anti-Doping Agency) compliant," PCB director of communications Ahsan Malik told AFP.
Three of the players - Younis Khan, Danish Kaneria and Yasir Arafat - are currently in England playing county cricket and their tests may be conducted abroad, Malik said.
The focus of these latest tests remains Akhtar and Asif, who tested positive for the banned steroid nandrolone in tests conducted internally in Pakistan before the ICC Champions Trophy last year. They were withdrawn from the Pakistan team for the tournament.
A PCB doping tribunal banned Akhtar for two years and Asif for one year, but the bans were controversially overturned by an internal tribunal on appeal.
Pakistan also conducted pre-World Cup tests in February in which Akhtar and Asif did not appear. The duo was then pulled out of the World Cup due to injuries on the day the team left for the West Indies.
Pakistan suffered a humiliating exit from the World Cup after a three-wicket loss to first-timers Ireland.
Malik said he hoped the team would be announced once the results of the latest tests were received from a Malaysian laboratory.
"We hope to get the results of these tests in time to announce the squad on Aug 11," said Malik, who denied that the tests are being done to avoid any embarrassment in the Twenty20 event.
"We have a policy to conduct dope tests for the last five years so it's nothing new," he said.
Asif returned to Pakistan's squad in the tri-series against Sri Lanka in Abu Dhabi in May, while Akhtar's return has been delayed after Pakistan's matches against Scotland and India - both in Scotland - were washed out earlier this month.
Both Akhtar and Asif are attending Pakistan's tune-up camp here. The team's new coach, Australian Geoff Lawson, is due to join them on August 20.
Lawson replaces Bob Woolmer who died during the World Cup in March.
Pakistan will open the Twenty20 World Cup against Scotland on September 12 before meeting arch rivals India two days later.