LONDON, Oct 17 (Reuters) - Northern Ireland's Democratic Unionist Party (DUP) said on Thursday it could not support Prime Minister Boris Johnson's Brexit agreement with the European Union because the deal was not in the British province's interests.

"These proposals are not, in our view, beneficial to the economic wellbeing of Northern Ireland and they undermine the integrity of the union," the party said, warning a parliamentary vote on Saturday was just the first stage in approving the deal.

"Saturday’s vote in parliament on the proposals will only be the start of a long process to get any Withdrawal Agreement Bill through the House of Commons," it added.

(Reporting by Guy Faulconbridge and Kate Holton; writing by Costas Pitas; editing by Stephen Addison)