The main area of focus of the trip was progressing free trade negotiations with the European Union.
O'Connor said a deal would be great for New Zealand and he would like to see an agreement in principal by the end of the year.
"Look, it's a market of 450 million people. They're all discerning high value customers for both services, technology and of course for our traditional meat, dairy and sheep meat products. So, you know, this is has been a valuable market and will be into the future."
A sensitive issue in discussions has been the EU's desire to protect over 2000 food and beverage 'Geographical Indications'.
The dairy industry here said it's open to changing the labelling on some products to make the country of origin clear - but unwilling to stop using cheese names such as feta and gruyere.
O'Connor said it's likely changes will need to be made - but wouldn't say how far they would go.
"The transition period and, and how much they have to change ultimately will be part of the final agreement and, and I guess the ability for the exporters to accommodate that. I think the dairy industry is aware of that.
"But overall, we're wanting to ensure that the trade deal offers more opportunities for the New Zealand dairy industry, even with changes that might be necessary."
While overseas O'Connor was able to speak with UK Secretary of State for International Trade Anne-Marie Trevelyan about the pending free trade deal between the United Kingdom and New Zealand.
The UK has signalled it was prepared to eliminate tariffs on New Zealand honey, wine and apples.
Access for New Zealand dairy and red meat is more contentious.
An agreement in principle was supposed to be signed by the end of August. O'Connor said things always pop up at the last minute, so it is taking longer than expected.
"We've made good progress, It's been a very short timeline for what is the substantive issue in potentially hugely valuable trade deal with a trusted partner.
"But we have worked through a few of the tricky issues, and we're confident that we can announce something within the next few weeks."
