Pub gardens, hairdressers and non-essential shops will reopen from April 12, after British Prime Minister Boris Johnson confirmed the next step of the road map for relaxing COVID-19 restrictions in England can go ahead as scheduled.

Speaking at a Downing Street news conference on Monday, Johnson said the "net success" of the lockdown and vaccine rollout is that step two of the road map will proceed as planned, meaning that next Monday shops, gyms, zoos, campsites, hairdressers and beer gardens will be allowed to reopen.

"We are setting out our road map to freedom and we are sticking to it," Johnson said. "We see no sign in our present data to think that we will have to deviate from the program.

"But it is by being cautious and monitoring the data at every stage and by following the rules, remembering hands, face, space and fresh air, that we hope, together, to make this roadmap to freedom irreversible."

Asked about mounting opposition in Parliament to the possibility of COVID passports being introduced, Johnson said that there is "no question" of people being asked to produce certificates when they go to the shops or pub gardens, adding "that is not being planned for step 3 either".

However, he said that the use of international vaccine passports is a certainty. The idea of vaccination status being useful for international travel is something "all countries are looking at" and "we need to deal with that", he said.

Johnson envisaged that nightclubs, sports events and theaters could require certificates, and ministers are looking at domestic certification further down the line, toward the summer.

He explained there are three ways COVID certification can be granted "for a big mass event" — immunity after contracting the novel coronavirus in the past six months, proof of vaccination, and a recent negative test.

Johnson said the government is being careful to avoid a system which is "discriminatory", as pregnant women cannot be vaccinated, and others cannot get vaccinations for medical reasons.

On international travel, the prime minister said he is "hopeful" that it can resume from May 17, but there are difficulties around "importing" virus variants.

"Obviously we are hopeful that we can get going from May 17 … but I do not wish to give hostages to fortune or to underestimate the difficulty we are seeing in some of the destination countries people might want to go to," he said. "We don't want to see the virus being reimported into this country from abroad."

With the Global Travel Taskforce due to report back  by April 12 with its recommendations aimed at facilitating a return to international travel, Johnson said he would then be able to set out "what is reasonable" for overseas travel.