CALCUTTA. - With between 75,000 and 100,000 East Pakistani civil war refugees still streaking daily into West Bengal state, the Indian government is embarking on a program to build about 10 new camps each capable of handling 500,000 people.

Estimates of the number of refugees in West Bengal now range from 4.9 million to 5.5 million.

The influx at the moment is greatest in the Bongaon area about 60 miles north of here, where cholera continues to be a great threat.

A British relief worker, Dr. Stewart Clarke said more than 500 new cholera victims were reported at the Bongaon district hospital last Tuesday, almost double the number on Monday .

The chief secretary for West Bengal, N.K. Sen Gupta, said yesterday the government hopes to ship about a million refugees out of the state by the end of next month. He said about 64,000 had already left West Bengal, mainly for a large camp at Mana in Central India.

Sen Gupta said the new camps being constructed would be segregated from the general population.

"After all, these people are foreigners," he said. "They have no passports. They should be properly identified, not only for our own internal security, but also to facilitate their return, if conditions are improved, to East Pakistan.

Meanwhile four British members of Parliament have ended a two-day tour of refugee camps in northeast India and flew to New Delhi today for talks with India's Prime Minister Indira Gandhi.

Arthur Bottomley, who is heading the British delegation, warned President Yahya Khan of Pakistan against the dangers of ''another Vietnam" in East Pakistan.

Bottomley told a meeting of Indian members of parliament and newsmen in New Delhi, "We have been told time and time again in India "What we don't want on the border of India is another Vietnam."

The British parliamentarians all condemned the Pakistan army action in East Pakistan since the civil war started last March .

Toby Jossel told reporters on arrival from Calcutta, "I have come to the conclusion that the Pakistan army in East Pakistan has gone far beyond what was necessary to maintain law and order and is acting in a manner which I can only describe as uncivilized."