Britain's government is confident its COVID-19 vaccination programme is secure after receiving guarantees from the European Union, trade minister Liz Truss said on Sunday, trying to smooth over a row about vaccine supplies.

Just a month after Britain completed its journey out of the EU's orbit, ties with Brussels were severely tested on Friday when the bloc's plan for export controls on vaccines included triggering an emergency clause in the earlier Brexit deals.

The move, which was quickly reversed, united Britain's politicians in criticism of the EU's threat to create a border it has long said it wanted to avoid between the British province of Northern Ireland and EU member Ireland.

"We know that that supply is secure, we're absolutely confident that we can continue to deliver our programme. We have received reassurance from the European Union that those contracts won't be disrupted," Truss told Sky News.

Keen to defuse a row that suggests mistrust between the two sides bred during Brexit talks may persist, Truss said she was pleased the EU had admitted its "mistake" and it was time for the two sides to work together.

But she pointedly added: 'It's vital we work together, it's vital we keep borders open, we resist vaccine nationalism and we resist protectionism.'

Truss did not rule out offering any excess supply to other nations, but only once Britain had vaccinated the most vulnerable in the country.

The EU has fallen far behind Britain and the United States in the race to vaccinate its public. It announced on Friday it would impose export controls on vaccines, widely seen as a threat to prevent doses from being sent to Britain.

But it was forced to reverse part of the announcement within hours, after both Britain and Ireland complained about plans to impose emergency export controls for vaccines across the land border between Ireland and Northern Ireland.