New Zealand has agreed to buy four Boeing P-8A Poseidon maritime patrol planes, Defence Minister Ron Mark said on Monday, strengthening surveillance capabilities as it works to counter the rise of new powers, such as China.  According to a Reuters report, Defense Minister Mark said the aircraft were acquired through the U.S. foreign military sales program and would cost NZ$2.34 billion ($1.6 billion), including training costs. The aircraft are to be operational in 2023.