Deputy First Minister Ieuan Wyn Jones has met Prime Minister Gordon Brown for the first time since both men took up their new posts.
Ieuan Wyn Jones and Gordon Brown are now government colleagues
They are both attending the British-Irish Council at Stormont.
Mr Jones was standing in for First Minister Rhodri Morgan who is recovering from an artery operation.
Last week, Plaid Cymru leader Mr Jones was confirmed as deputy first minister after his party agreed a coalition government with Labour in Cardiff Bay.
The conference was the first time Gordon Brown met the new leaders of the UK's devolved governments in his new capacity.
Mr Jones said the conference had reviewed progress made by the council on transport.
It is the first time the conference has been held at Stormont
"Fast, efficient and integrated transport links are vital for the sustained economic prosperity of all our administrations," said Mr Jones.
"We have recognised the need to improve public transport and to encourage the transfer of freight from our over-burdened roads to the rail network. The environmental benefits of this policy are obvious."
Northern Ireland First Minister, the Rev Ian Paisley and Deputy First Minister Martin McGuinness hosted the event, which was also attended by Scotland's First Minister Alex Salmond and Irish Taoiseach Bertie Ahern.
The British-Irish Council brings together eight governments representing Westminster, Dublin, devolved nations, the Channel Isles and the Isle of Man.
Ieuan Wyn Jones joined delegates including Gordon Brown
Since the council's first meeting in the 1990s, nationalists have come into power in Scotland and Wales and the DUP and Sinn Fein are dominant in Northern Ireland.
Mr Jones added that holding the council in the Stormont Parliament for the first time was "a historic occasion" and he wished his "most sincere good wishes" to the new Northern Ireland administration.
"The restoration of devolution was achieved as a result of the coming together, in a spirit of service to all the people of Northern Ireland, of two very distinct political traditions," he said.
"We in Wales have also seen a coming together of parties with different traditions, on the basis of a shared programme for government, and a shared commitment to improve the lives of all our people in all parts of Wales."
"I know that we will have the support of this council in taking that work forward."