Australia plans to significantly boost surveillance of Pacific Islands territorial waters, spending A$477 million ($310.72 million) on aerial patrols for illegal fishing fleets, tender documents viewed by Reuters show, as China takes steps towards sending its coast guard to the region.Australia's Prime Minister Anthony Albanese visited Fiji on Friday to discuss regional security, after the government of Prime Minister Sitiveni Rabuka approved a maritime security agreement that will see Australia fund a patrol boat for Fiji.Australia will fund commercial aerial patrols to support Pacific Island countries monitoring exclusive economic zones which span millions of kilometres of ocean, the documents show.Australia was in a "permanent contest" in the Pacific, Foreign Minister Penny Wong said on Friday."The maritime domain is an important part of ensuring a stable and secure region in which sovereignty is respected," she told reporters in Adelaide, when asked about the Reuters report."These countries, they have very large maritime zones, but sometimes very small islands, so making sure that the maritime domain is ... used in a way that complies with international law and international norms, that goes to sovereignty."