At least 290 people have been killed and 500 injured by a series of eight explosions targeting churches and hotels in Sri Lanka on Sunday night.

Ambonpola was "shocked" when he heard about Sri Lanka's deadliest attack since the civil war ended 10 years ago.

"Obviously our entire community here in Wollongong is in shock. We are still trying to recover from the magnitude of it all," he said.

"I still remember the civil war in our country. This just brought back all those memories, all those terrible memories. But these attacks are much worse."

Most of the dead are believed to have been Sri Lankans, with about 30 foreign citizens confirmed killed.

Ambonpola said fortunately the families of the 150 plus Sri Lankan students at UOW seemed to have escaped injury from the deadly bombs.

"My family and most of the students' families who are studying at UOW are back at [Sri Lanka]," he said.

"Luckily my mum and my youngest brother were here but my dad was in Colombo when this happened.

"He is safe and from all the people who have gotten back to us, all of the students' close families are alright as far as we know."

One of the eight explosions was at St Anthony's Church in Kochcikade, Colombo.

St Stebastian's church posted pictures of destruction inside the church on its Facebook page, showing blood on pews and the floor, and requested help from the public.

"My dad is updating me of the situation back in Colombo. He said people are still worried and they are afraid to go out," Ambonpola said.

"My dad even called me and told me not to go out today, even though I'm in Australia. He's that worried as we don't know the full story yet. Things are a bit unclear."

But Ambonpola added Sri Lankans worldwide were united in their efforts to overcome this tragedy.

"We've gone through this once and come out the other side. We can go through this again and recover."

Read more: 'Incredibly sad day' for Sri Lanka: PM

Authorities have arrested 24 people, and Sri Lanka's defence minister Ruwan Wijewardene said the culprits were religious extremists, but no group has yet claimed responsibility.

Ambonpola though questioned reports Sri Lanka had an "ethnic problem"

"This is an attack by terrorists against all Sri Lankans, who are standing together as one against this terrorist act.

"Here at UOW all of us, including Sinhalese, Muslims and Christians are going to church to light candles as a show of respect."

The Pray for Sri Lanka event is at Unanderra Presbyterian Church tonight from 7pm.

The UOW Sri Lankan Students' Society have also set up a GoFundMe page to support those affected by the Easter Sunday bombings.

Visit www.gofundme.com/sri-lanka039s-6-bombing-attacks to help or the group's Facebook page here for more details.