Pacific Islanders concerned about losing their native lands to rising sea levels have delivered their demands for climate change action almost to the prime minister's door.

About 50 people, including members of Sydney's Pacific Island community, on Saturday kayaked past Kirribilli House to Lady Martin's Beach, which is overlooked by Mr Turnbull's Point Piper mansion.

"If we want to protect these islands into the future, the Australian government must act now to keep fossil fuels in the ground," protester Joseph Sikulu said before signage reading "stand up for the Pacific" and "keep it in the ground" was delivered on Saturday.