In a letter to the prime minister, the travel association ABTA said: "We know that it is too early to put a specific date on the return to international travel and that there will be a need for flexibility in the approach, but what we need are some principles for restarting travel - recognising that the return to normal life will never be entirely risk-free."
The letter added that the government should recognise the travel industry cannot afford to wait until everyone in the UK is vaccinated, especially since there will be people who reject the vaccine, so "a practical and cost-effective testing regime" should be adopted.
During the pandemic, travel agents have seen an economic loss of 86% and 160,000 jobs have been lost, according to the Office for National Statistics.
As well as introducing more testing, ABTA wants the Foreign Office to issue travel advice in relation to COVID-19 on a regional basis, as opposed to a whole country, which was used after the first lockdown.
ABTA has also called for an extension to the furlough scheme, grants "that take account of the impact of international travel restrictions", and other support measures, such as business rates relief, into the next financial year to help firms meet their fixed costs.
Boris Johnson will set out his "roadmap" out of England's lockdown on Monday.
Meanwhile, Foreign Office minister James Cleverly said the government could not guarantee the current lockdown would be the last.
"We do want it to be the last lockdown, that's what we're working towards," he said, but added "no one can predict with complete certainty" what the virus will do.
And on the prospect of Britons being able to travel overseas for holidays this summer, he said: "At this stage we are not able to say what the situation will be for holidays this summer."