He welcomed Taoiseach (Irish prime minister) Enda Kenny's comments on a possible referendum on Irish unity.
DUP MP Ian Paisley said Mr Kenny was "being mischievous".
The taoiseach said Brexit talks should consider that a clause in the Good Friday Agreement could result in the calling of a referendum.
In his remarks to reporters on Monday at the annual MacGill Summer School in Glenties, County Donegal, Mr Kenny said the triggering of a border poll required "clear evidence of a majority of people wishing to leave the UK and join the Republic".
He added: "It may be, in the eyes of some, a fanciful theory but who knows what happens in 10, 20 years time?"
Adams responded by calling for all parties supporting a united Ireland "to discuss how best this can be achieved."
"In the context of the north being dragged out of the EU by England, there is now a greater opportunity to achieve this," he said.
North Antrim MP Mr Paisley said Secretary of State James Brokenshire and his predecessor, Theresa Villiers, had both ruled out holding a referendum.
"It's not going to happen," he said.
"We all know in the next nine months Enda Kenny is not going to be taoiseach. So, he's really just being mischievous.," Mr Paisley added.
Ulster Unionist MLA Jenny Palmer described Mr Kenny's comments as "much ado about nothing".
She said that, in the wake of the EU referendum, the Stormont executive's priority should be "to convince the people of Northern Ireland that they have a plan for the way forward for our economy, our farmers, our voluntary and community groups, our universities and everyone else who depends heavily on EU funding and support."

Weston played 19 league and cup games for the Chairboys last season after signing from Southend in June 2016.
The 29-year-old has made 327 career Football League appearances, having also played for Charlton, Brentford, Gillingham and Notts County.
He is Ebbsfleet's fourth signing since winning promotion from the National League South last season.
Details of the length of Weston's contract have not been disclosed.

Radio 1's audience fell by 3.2% in the last three months of 2016 compared with the previous quarter, while Radio 1Xtra fell 11.4% over the same period.
Capital saw its listenership drop by 3.1%, while the Kiss network saw its share fall by 3.5%,
Yet Kiss still has reason to be happy, as its breakfast show is now London's most popular commercial breakfast show.
The audience research body's figures also show Radio 4's Today programme recorded its highest ever audience.
The BBC station's flagship show went from 7 million weekly listeners in the last quarter of 2015 to 7.4 million in the last three months of 2016.
"In an era of fake news, echo chambers and significant shifts in global politics, the role of Radio 4's Today as the trusted guide to the world around us is more important than ever," said Bob Shennan, director of BBC radio and music.
Radio 3's breakfast show also did well, with an audience of 647,000 in the last quarter of 2016 signalling a 20% rise on the same period in 2015.
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Sinn FÃ©in leader Gerry Adams has said there is "a need to be open and imaginative" on new constitutional arrangements.
[NEXT_CONCEPT]
National League side Ebbsfleet have signed Wycombe winger Myles Weston on a free transfer.
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Most UK radio stations aimed at a young audience have seen their listeners fall, Rajar figures suggest.