New Zealand's being told to make the most of the chance to meet with 53 world leaders all at once.

Jacinda Ardern's in London for CHOGM and as part of that has had an audience with the Queen.

READ MORE: PM Ardern meets Queen - will give toast at Palace banquet

Former Commonwealth Secretary-General Sir Don McKinnon told Mike Hosking New Zealand is a small country - and needs to find friends all over the world.

"Every opportunity you get where your Prime Minister, you senior Ministers can be face to face with other Prime Ministers it is usually worthwhile."

Meanwhile, BBC diplomacy producer Stuart Hughes told Mike Hosking Queen Elizabeth was blunt and to-the-point in asking world leaders to pick her son to be the future leader of the Commonwealth.

The reigning monarch has addressed the Commonwealth Heads of Government Meeting in London, calling on leaders to appoint the Prince of Wales as her successor.

LISTEN ABOVE AS SIR DON MCKINNON AND STUART HUGHES SPEAK WITH MIKE HOSKING