Australian Prime Minister Scott Morrison has been criticised for telling an audience he is "blessed" not to have children with disabilities.

Mr Morrison made the remark during a town hall debate ahead of Australia's election, after being asked a question by a woman with an autistic son.

Opposition MPs and others said the comment was upsetting, with one saying "every child is a blessing".

Government MPs said the context of the comment had been lost in the backlash.

During Mr Morrison's debate with Labor leader Anthony Albanese, the woman - identified as Catherine - asked about funding for a disability support scheme.

"I've been told, to give my son the best future, I need to vote Labor. Can you please tell me what the future of the [National Disability Insurance Scheme] looks like under your government?"

The prime minister began by asking Catherine for her son's name. After she replied it was Ethan, Mr Morrison said: "Jenny and I have been blessed, we've got two children that don't - that haven't had to go through that."

"And so, for parents with children who are disabled, I can only try and understand your aspirations for those children."