BRUSSELS, Sept 14 (Reuters) - The European Commission is expected to outline by the end of September plans that could ease the movement of goods from Britain to Northern Ireland in an effort to ease tensions resulting from Brexit, EU diplomats said. The EU rejected a UK demand to renegotiate the new trading position of the British province. But a deputy head of the bloc"s executive Commission, Maros Sefcovic, last week promised "creative and solid new solutions" under the current deal. Under the so-called protocol, Britain agreed to leave some EU rules in place in Northern Ireland and accept checks on goods arriving there from the rest of the United Kingdom, in order to preserve an open land border with Ireland, an EU member state. But London has since said that was not working and must be changed. EU diplomats said the Commission"s new ideas, which also include greater involvement of politicians and others in Northern Ireland, would be announced this month. "Possible solutions would centre around making existing checks less laborious, limiting the amount of paperwork needed," said one EU diplomat who deals with Brexit, adding the Commission might propose legal changes on the 27 nations" side to give room for greater leniency towards Britain. The new package is expected to go beyond previous Commission proposals that included passage for guide dogs, simpler tagging for livestock and easier circulation of medicines, said a second diplomat. National ambassadors to the EU are due to discuss the plans on Wednesday, followed by national ministers who deal with European affairs at a meeting on Sept 21. The extension beyond the end of September of grace periods on further checks and trade limitations the EU deems necessary to protect its single market of 450 million people has given some space for talks. Britain"s Brexit minister David Frost said on Monday that the EU needed to move in negotiations of the protocol, warning that London could unilaterally suspend it. read more The Commission, which oversees EU-UK relations on behalf of the 27 EU countries, has said it is willing to interpret the protocol flexibly, but not renegotiate it, rejecting outright a British call to end oversight by the European Court of Justice.