Families were among a further 48 Sri Lankan unauthorised maritime arrivals (UMAs) returned to Colombo today after failing to meet Australia's international obligations, the Department of Immigration and Citizenship (DIAC) of Australia said.

The group, which consisted of 35 single adult males and 13 people in family groups including seven children, departed Christmas Island at 1pm AEST today to be flown back to the Sri Lankan capital. Their return takes the number of Sri Lankans sent home to more than 1300 - more than 1100 of them involuntarily - since August last year. A DIAC spokesman said returning the group to Sri Lankans sends a powerful message.

"When people arrive in Australia without a valid visa, any claims they make for their reasons to travel to Australia are assessed by the department," the spokesman said.

"If these claims are not covered by Australia's international obligations, they will be returned to their homeland wherever possible."

Under new rules announced on July 19, anyone - including a person from Sri Lanka - who arrives in Australia by boat without a visa no longer has the chance to settle in Australia.

"If they are not quickly returned to Colombo, they will be taken to Papua New Guinea or Nauru where their claims will be assessed," the spokesman said.

"These enhanced screening arrangements will continue and if they do not engage Australia's international obligations, people will be quickly returned to Sri Lanka," the spokesman said. "This is making it clear that those who pay smugglers are throwing their money away and risking their lives in the process."

People returned involuntarily do not have access to reintegration assistance.