In the dying days of the government, Prime Minister Walter Nash overruled security services advice and approved the naturalization of a European emigrant living in Tizard's constituency who had in his youth been linked with Marxist circles, but had lived in New Zealand for many years and had a New Zealand wife and children.

When United States Vice President Spiro Agnew visited Wellington in mid-January 1970, Tizard along with several other Labour Members of Parliament including Arthur Faulkner, Jonathan Hunt, and Martyn Finlay boycotted the state dinner to protest American policy in Vietnam.

However, other Labour MPs including Opposition Leader Norman Kirk attended the function which dealt with the Nixon Doctrine.

[16] Tizard and Muldoon (the outgoing finance minister) believed Kirk withheld the finance portfolio for personal reasons and that Kirk's ill health made him impatient to achieve his objectives and wanted to eliminate the possibility of progress being hampered by a potentially reluctant minister.

[17] Both Freer and Deputy Prime Minister Hugh Watt had favoured Tizard for Finance, but Kirk thought he was not steady enough for the role and was suspicious of him as an "intellectual".

He was elected in an exhaustive caucus ballot, in the final iteration he defeated the Minister of Defence Arthur Faulkner 28 votes to 26.

As Minister of Finance, Tizard's 1975 budget introduced a number of progressive measures, such as an expansion of spending on education which provided a standard bursary for all students in tertiary studies.

[17] After the surprise defeat of the Third Labour Government in 1975 Tizard remained on the front bench as both Deputy Leader of the Opposition and Shadow Minister of Finance.

[14] In 1983 when Lange became leader Tizard was dropped from the finance portfolio and made Shadow Minister of Energy instead.

[24] Tizard made no secret of his displeasure in the demotion stating "If he [Lange] wants to give jobs for the boys that is his business.

"[25] In the Fourth Labour Government he was elected to the cabinet, due to being one of the few MPs with previous ministerial experience.

[27] After attaining cabinet rank again he found himself amongst colleagues belonging to a younger generation of thought different from his own leading him to once again be blocked from an economic portfolio.

He turned his attention instead to safeguarding his portfolios from the privatisation agenda of finance minister Roger Douglas and his backers (the "Rogernomes"), fighting against energy corporatisation wherever he could.

[17] He was confronted with nearly all of the country's energy resources having been committed to the Think Big policies of the previous government which hampered his plans to convert New Zealand vehicles to alternative fuels.

[28] Despite their differences in the past, Tizard increasingly found himself on side with Lange who also came to oppose much of Douglas' agenda.

[14] During the government's second term Tizard retained only the Science and Technology portfolio, but was also appointed Minister of Defence from 1987 to 1990.

[29] As Minister of Defence he pushed for the approval of purchasing four new Anzac-class frigates which was contentious due to significant opposition to the idea from the Labour Party membership.

Angry with the outcome Tizard threatened to resign and force a by-election unless he could come to an agreement with the government over a car and housing arrangements for himself and his wife.

[32] Tizard was annoyed but not surprised with the loss saying "It's no skin off my nose if the public want to be misguided and vote for a bunch of splinters.

"[33] At the 1992 local-body elections he stood as a candidate for the newly created Auckland Regional Services Trust, but was unsuccessful.

[40] In the 2000 Queen's Birthday Honours, Tizard was appointed a Companion of the New Zealand Order of Merit, for public services.

[46] While Minister of Defence, following his second divorce, Tizard advertised in a Canadian Air Force magazine to find Beryl.