SYDNEY, July 23 (Reuters) - Australia's drug regulator has approved Pfizer-BioNTech's COVID-19 vaccine for use with children aged 12 to 15, Federal Health Minister Greg Hunt said on Friday (Jul 23), as the country fights an outbreak of the Delta variant in three states.

The Therapeutic Goods Administration has thoroughly assessed the domestic and international evidence before extending its approval for the Pfizer-BioNTech vaccine to be administered to this age group, Hunt said in a statement.

Similar clearances for the use of the vaccine in children were approved several weeks ago by regulators in the United States, European Union and Britain.

Up until now, the Pfizer-BioNTech vaccine had only been approved for use in Australia for people aged 16 years and over.

Australia's vaccination panel will advise on which groups of children should be prioritised for the roll-out of the vaccine and when it should be administered, Hunt said.

With just over 32,400 COVID-19 cases and 915 deaths, Australia has handled the pandemic much better than many other developed economies, but stop-and-start lockdowns and a sluggish vaccine roll-out have led to frustration.

Prime Minister Scott Morrison on Thursday apologised for the slow vaccination programme as his government looks to speed up inoculations and meet a target to vaccinate the adult population by end-2021.

So far, just under 15 per cent of the adult population has been fully vaccinated.