"Obsessive criticism" of Brexit must end, Liam Fox has said, urging opponents of the UK's departure from the EU to "lift their horizons".
Ahead of a visit to China, the international trade secretary said "attitudes needed to change" in 2018.
"Brexit is not a time bomb to be defused but a great opportunity to be embraced," he told Conservative Home.
Healthy foreign investment and bulging export order books showed confidence in the UK, he added.
The UK is scheduled to leave the EU on 29 March 2019, after which it hopes to be able to negotiate its own trade agreements with countries such as China.
The UK is hoping to begin a new phase of co-operation with Beijing in the run-up to Brexit, with more trade and investment in financial services, infrastructure and energy.
During his three-day trip to China - the latest in a succession of visits by British ministers - Mr Fox will seek to capitalise on what he said was the "continued explosion of interest" from China and other countries in the region in British technology and innovation.
'Vote of confidence'
In stopovers in Beijing and Shenzhen, Mr Fox will meet the Chinese Minister of Commerce Zhong Shan and the chairman of one of the world's largest insurance companies, Ma Mingzhe.
Ahead of the trip, Mr Fox - one of the biggest cheerleaders for Brexit in the cabinet - said the strength of the British economy belied what he said was the "wave of negativism" expressed in some quarters over the country's future economic prospects.
In an article for the Tory grassroots website, he said 2017 had seen the highest level of foreign direct investment projects in the UK's history while exporters' order books were "stronger than at any time since August 1988".
This "vote of confidence" from investors, he suggested, was at odds with the "self-defeating pessimism that is too often on show from certain politicians, commentators and media outlets".
"It is easy to get the impression that these people would rather see Britain fail than see Brexit succeed," he said, adding: "We need to get beyond the obsession with criticising Brexit, lift our horizons and be out there too."
Trump tax cuts
Critics of Brexit say it will take many years to negotiate individual trade deals with other countries and, even then, they are unlikely to replace all the benefits of existing deals struck by the EU.
At the same time, there is uncertainty over what kind of trading relationship the UK will have with the EU.
But Mr Fox said global trade growth was likely to come from outside the EU citing, among things, what he said was the "confident environment" for business fostered by US President Donald Trump's tax cutting agenda.
Mr Fox said his priority was to ensure the UK continued to derive maximum benefits from existing EU trade agreements with other countries ahead of Brexit while laying the ground for new bilateral deals afterwards.
China is the UK's eighth largest export market, worth £17bn.
The UK recently announced up to £25bn in financial support - including loan guarantees - for UK businesses trading with Chinese counterparts along key transport routes in what is known as the Belt and Road Initiative.
Ministers for many years have hailed what they claim is a "golden era" of economic relations between the two countries although tensions exist on other issues such as human rights and media censorship.