British Prime Minister Theresa May's minority government is still working towards an agreement with Northern Ireland's Democratic Unionist Party (DUP) to support May's minority government, a Conservative source says.

"Talks are ongoing with the DUP and we continue to work towards a confidence and supply arrangement," the source said on Tuesday.

"As we have said, both parties are committed to strengthening the Union (between the UK's member nations), combating terrorism, delivering Brexit and delivering prosperity across the whole United Kingdom.

"While our discussions continue it is important the government gets on with its business."

The comments come after earlier Sky news quoted an unidentified sources in the DUP as saying May's talks with DUP were not going as expected.

Sky quoted the sources as saying the DUP is urging May's government to give "greater focus" to the negotiations and that the DUP "can't be taken for granted".

May's botched gamble on a snap election lost her party its majority in the 650-seat British parliament so May is in talks with the DUP on getting their support to pass legislation and to avoid another election.

It comes the day before parliament is opened by the Queen, after the return following the election was delayed.