Not only have the men opposed each other in Dunedin North - for National and Labour respectively - in the previous three elections, they are also their parties’ health spokesmen.
But they may find themselves enjoying - or should that be enduring - some bipartisanship over the next few months.
Parliament has been wrangling with the fraught issue of medical cannabis for months now, and the Misuse of Drugs (Medicinal Cannabis) Amendment Bill returned for its second reading on Thursday.
The Bill treads a fine line.
There is little resistance to the idea that terminally ill people whose pain could best be eased by cannabis should be given relief - but likewise politicians whose stock in trade is being tough on crime tread gingerly when it comes to amending the Misuse of Drugs Act.
National has played clever politics here.It supported the Bill at its first reading - and supported it again this week.
This is motivated both by the recognition that change in this area looks inevitable, and a desire for recognition in creating the framework which will control the distribution and use of medical cannabis.
National has drafted a whole range of proposed amendments to the Bill, and the price for its support is that the proposals Mr Woodhouse is advancing - changes largely researched and drafted by Whangarei MP Dr Shane Reti - be accepted.
"The goal is to achieve an effective medicinal cannabis regime," Mr Woodhouse told Parliament.
"I hope we can still do that; I hope we can get bipartisan support."
Dr Clark did not mention National in his speech - an omission Mr Woodhouse termed a lack of good grace - but did say a number of changes would be made to improve the Bill.
So not a good start to their nascent working relationship.But, as Invercargill Labour MP Liz Craig’s debate contribution showed, there are issues the parties may reach a compromise on.
Dr Craig raised the questions of cost, quality control and standards, and the breadth of access to medicinal cannabis - all earlier previously advanced by her National rival.
"This is where Mr Woodhouse was indicating that that might go very, very broad," Dr Craig said.
"But the wording that I think will be used is ‘those with advanced, progressive, life-limiting conditions, who are nearing the ends of their lives’."
Other issues to be ventilated include licensing of cultivation, production and supply of medicinal cannabis; whether any therapeutic cannabis products should be smokable; and the use of cannabis for palliation, or the easing of symptoms.
This may be a sticking point.
Dr Clark sees palliation - easing symptoms without curing an underlying disease - as being appropriate for those nearing the end of their lives.
"I consider this a better description of the group of patients the compassionate provisions were designed for ... Approximately 25,000 New Zealanders could benefit from palliative care," he said.
"I expect this group of patients would be covered by the definition of palliation, but it is not known how many would choose to use illicit cannabis."
Mr Woodhouse responded that not only people who were terminally ill were receiving palliation.
"I have chronic arthritis, somebody with diabetes, Parkinson’s - the medicines that those patients take are palliation, and if they are in pain as a consequence of that, what Dr Clark has just announced is that this will be extended to those chronic conditions," he said.
"I suggest that there is a significant risk that that becomes a stalking horse for the decriminalising of cannabis."
All that said, Dr Clark calls the Bill "compassionate", while Mr Woodhouse wants the Bill to be "effective".
Neither position is so extreme middle ground cannot be found, should there be the will to do so.
Plenty for Dr Clark and Mr Woodhouse to discuss should they meet on the Monday red eye to Wellington.
A good week
It takes quite some effort to put the township of Lumsden on the political radar, but Clutha-Southland National MP Hamish Walker keeps doing just that.
The likely downgrading of the Lumsden Maternity Centre - barring any legal intervention - has been a hot issue there for months, and Mr Walker has done his bit to ensure that decision is defended by those who made it.
He presented written evidence in support of a 5000-strong petition on the issue earlier this week, and may have secured an appearance before the health select committee on the issue.
A bad week
Labour’s Dunedin South MP Clare Curran has been keeping a low profile as her annus horribilis comes to an end, but has received a boost from her part in organising a successful Labour conference in Dunedin.
However, she was back in the headlines for the wrong reasons this week, after a party booklet was put on display in local MSD offices.The last thing Ms Curran or her party would have wanted was more scrutiny at Question Time.
An indifferent week
New Zealand First’s southern MP Mark Patterson was given a golden chance on Wednesday when he - rather unexpectedly - found himself selected as his party’s lead speaker in the general debate.
He might have taken the chance to push any of the agricultural or regional issues he has been involved with, but instead delivered a confused impromptu speech which mixed lazy National bashing with some flattery of Shane Jones. A chance missed here.