LONDON — After the revelations by Edward J. Snowden of wholesale surveillance and the rapid development of communications technology, the British government is about to present a draft bill intended to clarify the state’s powers and increase transparency and oversight for intelligence agencies and the police.

The aim is to modernize and streamline the government’s surveillance powers, while trying to retain public confidence that the government will also protect the privacy of law-abiding citizens.

The draft legislation, known as the Investigatory Powers Bill and to be presented to Parliament on Wednesday, will inevitably be controversial, with critics already calling it the “snoopers’ charter.” It replaces a tougher draft that was killed in 2013 by the Liberal Democrats, then the coalition partner of the Conservatives.

This time, the majority Conservative government is stepping more cautiously, seeking parliamentary and public debate and consultation before coming up with a final bill expected in the spring. And the government is already suggesting that it has heard critics and will include judicial oversight for surveillance warrants.