Signs that warn tourists of lethal crocodiles in the Kakadu National Park are so weathered they cannot be read, while the roof of its Jim Jim ranger station is falling off, with large sheets of it hanging down like peeling sunburnt skin.

Many national parks around the country face a similar need for funding, to address issues from teeming feral pig numbers to inadequate housing for staff.

The federal government will provide an additional $262.3 million in the upcoming budget for Australia’s iconic national parks. The investment will roll out over four years, on top of previously committed funds.

Federal Environment Minister Tanya Plibersek will announce the boost on Wednesday, noting national parks have been underfunded for a decade.

“Programs to protect threatened species and eradicate invasive species have been woefully underfunded. This puts at risk the safety of staff and visitors, and compromises the ability to protect some of our most precious places, and the plants and animals that call them home,” she said.

“These natural treasures should be a source of national pride, but instead they are falling apart.”

She added that the funding boost will help ensure critical infrastructure works are carried out on ageing park infrastructure – much of which was built between the 1960s and 1990s.

Other repairs will include updating equipment, fixing inadequate signage, providing essential ranger housing, and refurbishing rundown facilities across Booderee National Park, Kakadu and Uluru-Kata Tjuta national parks, the Australian National Botanic Gardens, and 60 marine parks.