Nigeria has been added to the red list of countries from where people arriving must quarantine in a hotel for 10 days.
The Federal Government had on Wednesday confirmed three cases of the Omicron variant. They were linked to travellers from South Africa.
UK Health Secretary Sajid Javid said that Nigeria is second only to South Africa in terms of linked cases to Omicron.
He said: “Over the recent days we have learnt of a significant number of growing cases linked to travel with Nigeria.
“There are 27 cases already in England and that’s growing and Nigeria now is second only to South Africa in terms of linked cases to Omicron.”
Javid added the government had “been clear that we will take action if it is necessary”, adding it was important to remember vaccinations “are our first line of defence” and calling on people to get a booster dose of a COVID-19 vaccine when called to do so by the NHS.
Javid said only residents and citizens of the UK and Ireland travelling from Nigeria would be allowed entry into the region.
“In light of the most recent data we are taking further action to slow the incursion of the Omicron variant.
“From 4a.m. Monday, only UK/Irish citizens and residents travelling from Nigeria will be allowed entry and must isolate in a managed quarantine facility,” he said.
Javid said the tightened requirements would come into force from 04:00 GMT on Tuesday.
Travellers heading to the UK will now have to take a Covid test before their departure in an effort to limit spread of the virus, the government has said.
Travellers will be required to submit evidence of a negative lateral flow or PCR test to enter UK.
Currently people only need to self-isolate until they test negative within two days of arriving.
The moves come after pressure on the government to tighten the policy had been growing over the course of the week.