A New South Wales man with an asbestos-related disease has been awarded $1.3 million in damages, partly because of his reduced capacity to care for his grandchildren.

The Dust Diseases Tribunal has awarded the money to Mario Perez, who worked as a bus depot labourer at Chullora in Sydney's west from the 1970s until 1990.

The 68-year-old was exposed to asbestos from gaskets in bus engines and pipes and when a roof was removed in 1987.

The tribunal heard he has mesothelioma that has spread to his spine, and until his illness spent up to three days a week caring for his family.

Law firm Maurice Blackburn argued the care he provided for his grandchildren during his retirement and also for his wife needed to be taken into account in determining his payout.

Tribunal acting president Judge Jim Curtis found that under the Civil Liability Act 2002, Mr Perez should be entitled to damages in relation to his lost capacity to provide future domestic services to his family.

Theodora Ahilas, principal in Maurice Blackburn's asbestos law department, welcomed the tribunal's decision.

"We live in a world where grandparents are often very involved in caring for grandchildren and we are very pleased this has been recognised in this judgment," she said.

"Mr Perez was also the sole carer of his wife, who has suffered from a debilitating cardiac condition since contracting rheumatic fever as an adolescent.

"Mr Perez also cared for his son's infant twins on week days and his two granddaughters while their mother worked shift work.

"Understandably, Mr Perez will no longer be capable of providing these invaluable services to his family as his disease progresses and his condition deteriorates."