The combination of three screws, two piston engines and one low-pressure turbine had been pioneered in the New Zealand Shipping Company's refrigerated cargo liner Otaki, launched in 1908.

Her first class accommodation was amidships, spread over her main, upper, shelter and promenade decks and included two cabins de luxe, each with its own bathroom.

Her first class dining saloon, lounge and library, and second-class music and smoking rooms were all in Louis XVI style.

Mindful of the great loss of life on the Titanic in April 1912, the Union Company stressed that Niagara had enough lifeboats for all her passengers and crew.

[10] When Niagara reached Melbourne the Auckland Star called her "an unsinkable ship" and praised her as "one of the most palatial and up-to-date steamers seen in Australia".

Stressing her large cargo capacity, the newspaper said "She cannot fail to encourage trade between New Zealand and Canada", and that she would "inevitably aid the great work of consolidating the Empire".

On 15 August Niagara and another Union Company liner, Marama, were held for some days at Honolulu because the German cruiser SMS Leipzig was reported to be near the coast of British Columbia.

Engineers worked around the clock and completed the repair in 40 hours, enabling Niagara to leave the dock on 26 March[34] and return to service.

[36] By December 1915 there was a shortage of merchant seafarers in Sydney, and ships including Niagara had difficulty finding enough to make a full complement.

[39] On 12 October, Dr Hughes, Auckland's District Health Officer, sent GW Russell a telegram informing him that one influenza patient aboard Niagara had died of pneumonia.

Peter Fraser questioned GW Russell's response to the outbreak aboard Niagara, and Harry Holland called for a Royal Commission of inquiry.

However, the report suggested that the powers and duties of port health officers did not go far enough, and it called for "a regular procedure of constant supervision over the sanitary and hygienic conditions of the wharves and shipping".

[62] On the morning of 19 December 1927 the three-masted schooner Doris Crane was sailing from Fanning Island to San Francisco with a cargo of copra when fuel for her auxiliary diesel engine caught fire.

[63] Doris Crane had no wireless, but at 0400 hrs on 20 December Niagara's lookouts saw the glare of the fire from 20 nautical miles (37 km) away and she changed course to assist.

[68] On the evening of 17 July 1935 the 4,535 GRT cargo motor ship King Egbert collided with Niagara in fog in the Strait of Juan de Fuca about 40 nautical miles (74 km) off Victoria.

[69] King Egbert's bow was stove in, and Niagara's hull was damaged above the waterline on her port side forward, abreast of her number one hold.

[79] That April and May, Niagara set new wireless records by transmitting and receiving signals to and from both Australia and Canada throughout her voyage to Vancouver and back.

[82] Between 28 May and 9 June 1928 the Fokker F.VII aircraft Southern Cross made the World's first flight across the Pacific: from California via Fiji and Hawaii to Queensland.

[12][38] In 1931 the Union Company anticipated competition from Matson Line of the USA, which had ordered two new liners, Mariposa and Monterey, to run between the West Coast of the United States and Australia via Hawaii, Fiji and New Zealand.

Canadian Pacific's Chairman, Sir Edward Beatty, sought support from the governments of the UK, Canada, Australia, New Zealand and Fiji to improve Canadian-Australasian's trans-pacific service.

[100] In July 1939 Sir Edward Beatty stated that the cost of shipbuilding had now risen too high for new ships to be ordered for the transpacific route.

Instead there was a proposal that the 20,021 GRT Canadian Pacific liner Duchess of York, or one of her sister ships, could be modified for trans-pacific service to replace Niagara.

[103] On the night of 13–14 June 1940 the German auxiliary cruiser Orion laid a field of 228 contact mines[104] across the mouth of the Hauraki Gulf:[105][106] in a bid to blockade Auckland,[107] New Zealand's largest commercial port.

[105] Her sinking ended a 27-year career in which Niagara made 162 round trips between Australia, New Zealand and Canada and sailed nearly 2,500,000 nautical miles (4,600,000 km).

[113] Under conditions of wartime secrecy, news reports at the time did not disclose that it was Huddart Parker's 9,576 GRT Trans-Tasman liner Wanganella.

in 1932 an Italian salvage contractor had recovered sovereigns and silver bullion worth £1 million from the wreck of the P&O liner Egypt in the English Channel.

[119] It is made of manganese bronze, has several small quartz glass portholes, is built to withstand pressure to a depth of 125 fathoms (229 m) and weighs three tonnes.

In 1988 marine salvage specialist Keith Gordon from Albany, New Zealand explored the wreck with a remotely operated underwater vehicle.

[107] Another escape was photographed in 2000,[105] when marine environmentalist Wade Doak described the wreck as a "ticking timebomb", threatening Whangārei's mangrove systems and the Hen and Chickens Islands nature reserve.

[106] Environmentalists including Doak,[127] salvage experts, and Auckland politician Mike Lee have called for the oil to be extracted from the wreck to prevent such a disaster.