The party has been calling for a vote for Northern Ireland to leave the UK and unite with the Republic of Ireland since Britain voted to leave the European Union.
The majority of voters in Northern Ireland voted to remain in the EU, fuelling Irish nationalists who say a united Ireland would save them from Brexit.
After supporting the Catalan separatist movement in Spain, Sinn Fein is now demanding a referendum within in the next five years.
Immediately after the referendum on October 1 the party praised the “enormous courage” of the Catalan people, and held vigils in Belfast and Londonderry in solidarity.
Sinn Féin is for a new, united and agreed Irelan
A spokesman for the party said: “Sinn Féin is for a new, united and agreed Ireland.
“Sinn Féin has called for a referendum on unity to be held within the next five years and support for that position is growing.
“We want an informed debate on all the issues around a new united and agreed Ireland where we look at building an Ireland for all, for nationalists, republicans, unionists, loyalists and others.”
Earlier this month Mr Adams had a 20 minute phone conversation with Catalonia President Carles Puidgemont.
After the call he said: “The only way to end any dispute, particularly one as complex as this, is through inclusive dialogue and mediation.
“President Puigdemont assured me that he and his government stand ready to talk. That has always been their priority.”
Mr Adams also called on the international community “to urgently intervene and support the call for dialogue and mediation”.
Earlier this year the DUP slammed calls for a border referendum, saying it would have a “destabilising effect” on the country.
Sinn Fein want a border referendum in the next five years
A spokeswoman for the party said: “We do not support such a poll being called. Our focus is on working for the people of Northern Ireland.”
The party also hit out at Sinn Fein’s support of the referendum.
DUP councillor David Ramsey said: “We are embroiling ourselves in something that is being deemed illegal, which is a major issue for us.”
Christopher Smyth, UUP councillor for Fermanagh and Omagh District Council, said Sinn Fein’s support of the independence referendum was “more about Sinn Fein trying to be seen to be doing something in the absence of an assembly” as Stormont remains suspended after the collapse of the power sharing agreement between Northern Irish parties.
Opinion polls have shown a majority of people in Northern Ireland want to remain part of the UK
The leader of the SDLP, Colm Eastwood, called for a post-Brexit referendum on creating a united Ireland.
He said: “I think that we need to have one after Brexit, when the dust settles.”
But Independent MLA Claire Sugden said the calls for a border poll in Northern Ireland were “premature”.
Northern Ireland has been without a devolved government since the assembly collapsed in January when deputy first minister Martin McGuinness resigned.
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Under the 1998 Good Friday Agreement peace deal, the British government can call a referendum if it appears likely a majority of those voting would seek to form part of a united Ireland.
But Northern Ireland’s Secretary of State James Brokenshire said in July last year that he did not believe the conditions for calling a referendum had been met.
Opinion polls in the past have shown a majority of people in Northern Ireland want to remain part of the United Kingdom.
An IPSOS-MORI poll in September found only 22 percent of 1,000 voters questioned said they would support a united Ireland while 63 percent said they would prefer to remain part of the UK.