The UK-Australia trade relationship was worth £13.9 billion past year and is set to grow under the deal, creating opportunities for businesses and producers in every part of the UK.
Boris Johnson has said he is also supporting farmers to increase their exports overseas, by opening up new markets in the Indo-Pacific.
The broad terms of the agreement were settled over dinner in No 10 on Monday evening (14 June), Australia's minister for trade Dan Tehan said.
"Apart from the extra checks that will apply following the trade agreement reached last December, the threat to our markets is the biggest fallout for Irish farmers from the vote almost five years ago", he said.
A Welsh Government spokesperson said: "We understand an agreement has been reached on the UK-Australia free trade agreement (FTA)".
Karen Betts, chief executive of the Scotch Whisky Association, said the deal would help producers continue to expand Australia export markets, which have nearly doubled in size over the past decade, but said the industry hoped to get further legal protections.
90% of all exports from Northern Ireland to Australia are machinery and manufacturing goods - used extensively in Australia's mining, quarrying and recycling sectors. The new deal will mean that tariffs on such products are gradually phased out.
Vehicle manufacturers in the midlands and north of England will see tariffs of up to 5% cut, boosting demand for their exports.
The Department for International Trade has previously said any UK-Australia deal would include protections for the farming industry and not impact the high standards adhered to in the UK.
This deal delivers for Britain and shows what we can achieve as a sovereign trading nation.