BELFAST (Reuters) - Northern Ireland lawmakers on Tuesday voted in favour of continuing key parts of post-Brexit trade rules for the region, but opposition from pro-British unionist politicians triggered an independent review into the arrangements.

The specific arrangements for Northern Ireland, which shares an open border with European Union (EU) member Ireland, have dominated politics in the British-ruled region for years, and led to a two-year boycott of the devolved assembly by the main pro-British party until the rules were tweaked in January.

The assembly voted by 48 votes to 36 to continue to follow EU rules on the free movement of goods to avoid the need for a hard border with Ireland, the first so-called democratic consent vote allowed for under the Windsor Framework deal.

Unlike legislation on devolved matters that requires the support of a majority of both Irish nationalists and unionists, the vote needed a simple majority and was backed, as expected, by all nationalists and the cross-community Alliance Party.

However the total opposition from unionists, who want to remove the remaining trade frictions between Northern Ireland and the rest of the United Kingdom, means London must do an independent review into the functioning of the trade rules.

"The government remains committed to implementing the Windsor Framework in good faith and protecting the UK internal market, in a way that offers stability and works for Northern Ireland, for businesses, and for traders," Britain's Northern Ireland Minister Hilary Benn said in a statement.

The scope for any changes to the framework under this review will be extremely limited, said David Phinnemore, politics professor at Queen's University Belfast.

Polling conducted by Queen's University during 2024 indicated that 56% of voters in Northern Ireland wanted lawmakers to vote in favour of continuing with the trade rules, while just under a third wanted them to vote against.

The lack of unionist support also means the next consent vote will take place in four years' time, rather than eight had a majority of unionists and nationalists backed it

(Reporting by Amanda Ferguson; Writing by Padraic Halpin; Editing by Catarina Demony and Daniel Wallis)

By Amanda Ferguson