Taiwan lives under the constant threat of invasion by China, which sees the self-ruled democratic island as part of its territory to be brought into its fold, by force if necessary.

Beijing has ramped up pressure -- including record incursions by warplanes -- since Tsai Ing-wen became Taiwan's president in 2016, as she views the island as a sovereign nation and not part of "one China".

Beijing is strengthening its air, sea and land strike capabilities against the island, Taiwan's defence ministry said in a biennial report released Tuesday.

Those capabilities include imposing a "blockade against our critical harbours, airports and outbound flight routes, to cut off our air and sea lines of communication," the report added.

The report also warned that China is capable of striking all of Taiwan with its missile arsenal, including ballistic and cruise variants, and is also beefing up its ability to launch amphibious assaults on the island.

Taiwan's defence minister warned last month that military tensions with China were at their highest in four decades, after record incursions by Chinese warplanes into the island's air defence identification zone.

The zone is not the same as Taiwan's territorial airspace but includes a far greater area that overlaps with part of China's own air defence identification zone.

China's "frequent manipulation of grey zone threats" such as the warplane incursions, as well as other methods of warfare including cyberattacks, are aimed at "seizing Taiwan without a fight", the defence ministry report said Tuesday.