It will take a medical miracle and deep pockets to give Bangladeshi twins joined at the head the chance to lead separate lives.

The future of 12-month-old orphans Krishna and Trishna rests with a team of Melbourne specialists and generous Australians after government funds were ruled out yesterday.

The medical battle began last Sunday week when doctors worked for four hours to correct a life-threatening problem caused by a shared vein.

It was the first step in a risky, six-month plan to save the girls.

The cost of separating and caring for the twins is expected to hit $400,000.

But Acting Premier Rob Hulls said the State Government would not be chipping in.

"It's understandable that kids from around the world want to get access to a great hospital," Hulls said.

He said the hospital was welcome to dip into its discretionary funds to cover the twin's post-operative care.

AusAid, the Federal Government's foreign aid program, said Australia already provided aid to Bangladesh and the treatment of the twins was a health issue.

A spokesman for Health Minister Nicola Roxon said he was unable to comment.

But Altruism Australia founder and director Shane Holst said governments should show leadership by helping the twins and other sick children from overseas get medical treatment in Australia.

"When our compassion becomes so strong we can stand up and set examples like that, I think that's a wonderful thing," Holst said.

The twins, who had their first birthday at the Royal Children's Hospital on December 13, were brought to Melbourne by Moira Kelly's Children First Foundation after being found in an orphanage by an Australian aid worker.

An anonymous benefactor has provided $250,000 to cover the costs of surgery and hospital care.

Ms Kelly said another $150,000 would be needed after the girls left hospital — for nursing, therapy, transport and accommodation.

She urged Australians to dig deep.

Ms Kelly, who is joint guardian of the twins, said she decided to go ahead with the separation after consulting ethics experts and 20 doctors.

"It was the hardest three days of my life," she said.

Ms Kelly said the twins were likely to spend about six months in hospital after being separated and would need medical care in Australia for two years.

She said she hoped they could return to Bangladesh for primary school, but come back to Australia on scholarship for secondary school.

The first of four delicate operations was performed because Krishna, the smaller of the twins, was getting an overload of blood from a shared vein, causing heart problems.

A specialist team from the RCH and Royal Melbourne Hospitals inserted coils into the vein through a catheter.

RCH director of neurology Wirginia Maixner said it was a complete success.

The girls' brains are not joined but they share a complex web of veins supporting them.

Miss Maixner said the girls faced certain death if they were not separated.