Prime Minister Ranil Wickremesinghe said since police investigations against the Muslim ministers over their alleged links to NTJ had drawn a blank, they were free to re-join the government.
They were intercepted and jailed in the UAE for six months before they were deported to India earlier in July.
His statement came as relatives of the victims of the terrorist attack two years ago criticised the security authorities for not doing enough to keep Khurram Butt under surveillance.
The National Investigation Agency (NIA) and the state police forces have registered cases against IS members and sympathisers and have arrested 155 accused from across the country so far.
Reframing the conflict in Kashmir will provide scope for a peace process to kick off. While there is little appetite in governments to engage with ending terrorism politically, ending insurgency is only possible through political means.
The Kashmir police has rightly characterised the ISIS announcement of Wilaya-e-Hind as propaganda, since there are no ISIS remnants in Kashmir. The claim is a clear bid to break out of its current status as a virtual threat confined to cyber space.
The Sanctions Committee said ISIS-K had carried out numerous attacks since its formation that have killed more than 150 people.
ISIS did not elaborate on the branch's geographical remit as it mentioned the name of its new branch in a low-key announcement.
Wickremesinghe said all those directly linked to the Easter Sunday attacks were either killed or are in custody.
The probe agency said in a statement that it carried out the searches at the houses of three suspects -- two in Kasaragod and one in Palakkad.
The country's police chiefs are urging churches and mosques in Britain to have counter-terrorism training because of fears of further attacks in the wake of the Sri Lanka terrorist strikes, which claimed hundreds of lives over Easter.
The MEA said Sri Lanka has beefed up security in the country but a nation-wide emergency including night time curfew has been in place which may affect travel within Sri Lanka.
The Islamic State group has claimed responsibility for the Easter terror attacks on three Catholic churches and three luxury hotels that claimed 253 lives but the government has blamed a local Islamist extremist group National Tawheed Jamath (NTJ) for the bombings.
The group did not give evidence for its claim.
If the National Thowheeth Jama’ath is really the source of problem, then its presence in Tamil Nadu needs to be examined carefully. If the ISIS has indeed played a role, then the impact of the ISIS ideology will have to be assessed.
Saturday's announcement will go down as a symbolic date in a war that changed the face of the region and spurred a spate of global terror attacks.
Saudi Arabia also announced on March 1 it had revoked the citizenship of Hamza bin Laden via a royal decree in November.
The attack on January 27 on a predominantly Muslim island in the country's volatile south wounded 81 people and was one of the deadliest in recent years in a region long plagued by instability.
The arrest was made on January 26 from Mumbra in neighbouring Thane district and a laptop, tablet computer, hard disk, pen drives, router, mobile phones and diaries were seized from his residence, an Anti-Terrorism Squad official said.
The agency has arrested 12 people in this connection since December 26 last year.
Trump's surprise announcement in December that appeared to signal a rapid withdrawal of the American forces from war-torn Syria, where the US special forces play an important role in supporting local forces fighting the dreaded ISIS group caused a diplomatic storm.
The court remanded the other five accused in judicial custody after the agency said they were not required for custodial interrogation.
Iraq declared "victory" over IS at the end of 2017 after a three-year war against the jihadists, who once controlled nearly a third of the country as well as swathes of neighbouring Syria.
NIA sought 15-day custodial interrogation of the 10 accused who were arrested from various parts of the national capital and Uttar Pradesh.
The agency conducted searches across 16 locations in Uttar Pradesh and New Delhi in connection with its probe into the new ISIS module called 'Harkat ul Harb e Islam'.